Jerome V Moloney

Interests

Teaching

Advanced undergraduate courses in Applied Mathematics and direct supervision of graduate students towards Ph.D's in Optical Sciences and Applied Mathematics.

Research

Space time complexity in passive and active nonlinear optical systems. Bifurcation analysis, dynamical systems and analysis of pde's related to nonlinear optics. Study of nonlinear systems with large separations in time and space scales. Computational science/photonics, algorithm development for novel computing architectures and massively parallel computing systems. Modeling semiconductor lasers, high power femtosecond light strings and nanoscale photonics devices.

Courses

Scholarly Contributions

Books

• Moloney, J. V., & Newell, A. C. (2004). Nonlinear optics. Westview Press.

Chapters

• McLaughlin, D., Newell, A., & Moloney, J. (1986). Coherence and chaos in passive nonlinear optical systems. In Optical Bistability III(pp 314--318). Springer.
• Moloney, J., Newell, A., & McLaughlin, D. (1984). Transverse Solitary Waves in a Dispersive Ring Bistable Cavity Containing a Saturable Nonlinearity. In Optical Bistability 2(pp 407--414). Springer.

Journals/Publications

• Bondaz, T. A., McInerney, J. G., Moloney, J. V., & Jones, R. J. (2023). Broadband 1.5 GHz VECSEL-Based Laser System for High Speed Multicontrast Nonlinear Imaging. IEEE Photonics Technology Letters, 35(11), 589--592.
• Chatterjee, S., Dobener, F., Fuchs, C., Hader, J., Koch, S. W., Lorenz, J., Meier, T., Moloney, J. V., Ngo, C., Schäfer, F., Stein, M., Steiner, J. T., Stolz, W., & Volz, K. (2023).

  Gain recovery dynamics in active type-II semiconductor heterostructures

  . Applied Physics Letters, 122(8), 082104. doi:10.1063/5.0128777
• Hader, J., Neuhaus, J., Moloney, J. V., & Koch, S. W. (2023). Coulomb enhancement of high harmonic generation in monolayer transition metal dichalcogenides. Optics Letters, 48(8), 2094--2097.
• Hagen, M. K., Hader, J., & Moloney, J. V. (2023). Symmetry-conserving treatment of the random-phase problem in nonlinear coherent optics modeling in solids. Physical Review A, 108(3), 033510.
• Kolesik, M., & Moloney, J. V. (2023). Numerical discreteness and dephasing in high-harmonic calculations in solids. Physical Review B, 108(11), 115433.
• Panagiotopoulos, P., Heinz, J., Kolesik, M., & Moloney, J. V. (2023). Higher order long-wave infrared Bessel beams generating tubular plasma waveguides in the atmosphere. Optics Continuum, 2(2), 449--455.
• Parks, A. M., Moloney, J. V., & Brabec, T. (2023). Gauge Invariant Formulation of the Semiconductor Bloch Equations. Physical Review Letters, 131(23), 236902.
• Rudenko, A., Han, A., & Moloney, J. V. (2023). Trade-Off between Second-and Third-Order Nonlinearities, Ultrafast Free Carrier Absorption and Material Damage in Silicon Nanoparticles. Advanced Optical Materials, 11(2), 2201654.
• Rudenko, A., Moloney, J. V., & Polynkin, P. (2023). Ionization clamping in ultrafast optical breakdown of transparent solids. Physical Review Applied, 20, 064035. doi:10.1103/PhysRevApplied.20.064035
• Sch\"afer, F., Stein, M., Lorenz, J., Dobener, F., Ngo, C., Steiner, J. T., Fuchs, C., Stolz, W., Volz, K., Meier, T., & others, . (2023). Gain recovery dynamics in active type-II semiconductor heterostructures. Applied Physics Letters, 122(8).
• Zalogina, A., Carletti, L., Rudenko, A., Moloney, J. V., Tripathi, A., Lee, H., Shadrivov, I., Park, H., Kivshar, Y., & Kruk, S. S. (2023).

  High-harmonic generation from a subwavelength dielectric resonator

  . Science Advances, 9(17). doi:10.1126/sciadv.adg2655
• Zalogina, A., Carletti, L., Rudenko, A., Moloney, J. V., Tripathi, A., Lee, H., Shadrivov, I., Park, H., Kivshar, Y., & Kruk, S. S. (2023). High-harmonic generation from a subwavelength dielectric resonator. Science Advances, 9(17), eadg2655.
• Moloney, J. V. (2022). Few-cycle 10µm multi-terawatt pulse self-compression in a gas-filled multi-pass cell: a numerical experiment. Journal of the Optical Society of America, B, 39, 266. doi:https://doi.org/10.1364/JOSAB.437870
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  M. G. Hastings, P. Panagiotopoulos, M. Kolesik, V. Hasson, S. Tochitsky, and J. V. Moloney, "Few-cycle 10µm multi-terawatt pulse self-compression in a gas-filled multi-pass cell: a numerical experiment," Journal of the Optical Society of America B 39, 266 (2022)
• Moloney, J. V. (2022). On the importance of electron-electron and electron-phonon scatterings and energy renormalizations during carrier relaxation in monolayer transition-metal dichalcogenides. Journal of Physics: Condensed Matter, 34, 285601. doi:https://doi.org/10.1088/1361-648x/ac699e
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  J. Hader, J. Neuhaus, J. V. Moloney, and S. W. Koch “On the importance of electron-electron and electron-phonon scatterings and energy renormalizations during carrier relaxation in monolayer transition-metal dichalcogenides” Journal of Physics: Condensed Matter, 34 285601 (2022)
• Moloney, J. V. (2022). A. Rudenko, A. Han, and J.V. Moloney, "Trade-off between second- and third-order nonlinearities, ultrafast free carrier absorption and material damage in silicon nanoparticles,”Adv. Optical Mater, 2201654 (2022). Advanced Optical Materials, 11. doi:https://doi.org/10.1002/adom.202201654
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  A. Rudenko, A. Han, and J.V. Moloney, "Trade-off between second- and third-order nonlinearities, ultrafast free carrier absorption and material damage in silicon nanoparticles,”Adv. Optical Mater, 2201654 (2022)
• Moloney, J. V. (2022). Colliding Pulse Mode Locking and Nonequilibrium Carrier Dynamics within Vertical External-Cavity Surface-Emitting Lasers. Physical Review Applied, 18, 024006. doi:https://doi.org/10.1103/PhysRevApplied.18.024006
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  S. A. McLaren, I. Kilen, and J. V. Moloney. "Colliding Pulse Mode Locking and Nonequilibrium Carrier Dynamics within Vertical External-Cavity Surface-Emitting Lasers." Physical Review Applied 18, 024006 no. 2 (2022)
• Moloney, J. V., Hader, J., Liebscher, S. C., & Koch, S. W. (2022). Intrinsic carrier losses in tellurium due to radiative and Auger recombinations. Applied Physics Letters, 121(19), 192103. doi:10.1063/5.0115784
• Moloney, J. V., Han, A., & Babicheva, V. E. (2022). Applicability of multipole decomposition to plasmonic- and dielectric-lattice resonances. The Journal of Chemical Physics, 156(11), 114104. doi:10.1063/5.0082005
• Moloney, J. V., Kolesik, M., & Panagiotopoulos, P. (2022). Nonlinear localization of high energy long wave laser pulses in fully correlated 3D turbulence. Optics Letters, 47(7), 1782. doi:10.1364/ol.452045
• Moloney, J. V., Rudenko, A., Hagen, M. K., Hader, J., & Koch, S. W. (2022). Self-consistent Maxwell–Bloch model for high-order harmonic generation in nanostructured semiconductors. Photonics Research, 10(9), 2099. doi:10.1364/prj.463258
• Moloney, J. V. (2021). Coupled kinetic Boltzmann electromagnetic approach for intense ultrashort laser excitation of plasmonic nanostructures. Physical Review B, 104, 035418.
• Moloney, J. V. (2021). Generation of long homogeneous plasma channels with high power long-wave IR pulsed Bessel beams. Optics Letters, 46, 5457.
• Moloney, J. V. (2021). Microscopic Theory for the Incoherent Resonant and Coherent Off-Resonant Optical Response of Tellurium. Physical Review B, 104, 165201.
• Moloney, J. V. (2021). Microscopic modeling of non-normal incidence vertical external cavity surface-emitting laser cavities. Applied. Phys. Letts., 118, 121103.
• Moloney, J. V. (2021). Numerical study of spatial propagation dynamics and energy delivery of TW square-aperture CO2 laser pulses in the atmosphere. Journal of the Optical Society of America B, 38(4), 1214.
• Moloney, J. V. (2021). Submonolayer Quantum-Dot Based Saturable Absorber for Femtosecond Pulse Generation. Journal of Electronic Materials, 50, 2710.
• Moloney, J. V., Kilen, I., & McLaren, S. (2021). Microscopic modeling of non-normal incidence vertical external cavity surface-emitting laser cavities. Applied Physics Letters, 118(12), 121103. doi:10.1063/5.0040185
• Moloney, J. V., Panagiotopoulos, P., Kolesik, M., & Tochitsky, S. (2021). Generation of long homogeneous plasma channels with high power long-wave IR pulsed Bessel beams. Optics Letters, 46(21), 5457. doi:10.1364/ol.438633
• Han, A., Dineen, C., Babicheva, V. E., & Moloney, J. V. (2020). Second harmonic generation in metasurfaces with multipole resonant coupling. Nanophotonics, 1(ahead-of-print).
• Hofstrand, A., & Moloney, J. (2020). Subcycle spatiotemporal compression of infrared pulses in Chi2 semiconductors. Optics Letters, 45, 6006-6009.
• Hofstrand, A., & Moloney, J. V. (2020). Optical Carrier-Wave Subcycle Structures Associated with Supercritical Collapse of Long-Wavelength Intense Pulses Propagating in Weakly Anomalously Dispersive Media. Physical review letters, 124(4), 043901.
• Kilen, I., Kolesik, M., Hader, J., Moloney, J. V., Huttner, U., Hagen, M. K., & Koch, S. W. (2020). Propagation Induced Dephasing in Semiconductor High-Harmonic Generation. Physical review letters, 125(8), 083901.
• Liebscher, S. C., Bannow, L. C., Hader, J., Moloney, J. V., & Koch, S. W. (2020). Extension of the LDA-1/2 method to the material class of bismuth containing III--V semiconductors. AIP Advances, 10(11), 115003.
• McLaren, S., Moloney, J. V., Kilen, I., Kilen, I., Moloney, J. V., & McLaren, S. (2020). Microscopic modeling of transverse mode instabilities in mode-locked vertical external-cavity surface-emitting lasers. Applied Physics Letters, 116(3), 031102.
• Meckbach, L., Hader, J., Huttner, U., Neuhaus, J., Steiner, J. T., Stroucken, T., Moloney, J. V., & Koch, S. W. (2020). Ultrafast band-gap renormalization and build-up of optical gain in monolayer MoTe 2. Physical Review B, 101(7), 075401.
• Moloney, J. V., Dineen, C., Han, A., & Babicheva, V. E. (2020). Second harmonic generation in metasurfaces with multipole resonant coupling. Nanophotonics, 9(11), 3545-3556. doi:10.1515/nanoph-2020-0193
• Panagiotopoulos, P., Hastings, M. G., Kolesik, M., Tochitsky, S., & Moloney, J. V. (2020). Multi-terawatt femtosecond 10 um laser pulses by self-compression in a CO 2 cell. OSA Continuum, 3(11), 3040--3047.
• Rockmore, R., Gibson, R., Moloney, J. V., & Jones, R. J. (2020). VECSEL-based virtually imaged phased array spectrometer for rapid gas phase detection in the mid-infrared. Optics Letters, 45(20), 5796--5799.
• Rudenko, A., & Moloney, J. V. (2020). Tunable Near-to Far-Infrared Optical Breakdown in Nonlinear Interactions of Ultrashort Laser Pulses with Water Microdroplets in Ambient Air. Advanced Photonics Research, 1(2), 2000029.
• Rudenko, A., Rosenow, P., Hasson, V., & Moloney, J. V. (2020). Plasma-free water droplet shattering by long-wave infrared ultrashort pulses for efficient fog clearing. Optica, 7(2), 115--122.
• Babicheva, V. E., & Moloney, J. V. (2019). Lattice Zenneck Modes on Subwavelength Antennas. LASER & PHOTONICS REVIEWS, 13(2).
• Bondaz, T., Laurain, A., Moloney, J. V., & McInerney, J. G. (2019). Generation and Stabilization of Continuous-Wave THz Emission From a Bi-Color VECSEL. IEEE PHOTONICS TECHNOLOGY LETTERS, 31(19), 1569-1572.
• Hastings, M. G., Werner, K., Schweinsberg, A., Wilmer, B. L., Austin, D., Wolfe, C. M., Ensley, T. R., Vanderhoef, L., Valenzuela, A., Chowdhury, E., Moloney, J. V., & Kolesik, M. (2019). Modeling Harmonic Generation in Polycrystalline ZnSe. 2019 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO).
• Hofstrand, A., Jakobsen, P., & Moloney, J. V. (2019). Bidirectional shooting method for extreme nonlinear optics. PHYSICAL REVIEW A, 100(5).
• Laurain, A., Hader, J., & Moloney, J. V. (2019). Modeling and optimization of transverse modes in vertical-external-cavity surface-emitting lasers. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS, 36(4), 847-854.
• Matteo, D., Pigeon, J., Tochitsky, S. Y., Huttner, U., Kira, M., Koch, S. W., Moloney, J. V., & Joshi, C. (2019). Control of the nonlinear response of bulk GaAs induced by long-wavelength infrared pulses. OPTICS EXPRESS, 27(21), 30462-30472.
• Matteo, D., Pigeon, J., Tochitsky, S., Huttner, U., Kira, M., Koch, S. W., Moloney, J. V., Joshi, C., & Joshi, C. (2019). Measurements of the Nonlinear Optical Response of Semiconductors with Intense 10µm Laser Pulses. Frontiers in Optics. doi:10.1364/fio.2019.jw3a.53
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  We measure four-wave mixing efficiency and nonlinear absorption in GaAs, Ge, and ZnSe using a GW/cm2 CO2 laser. At high fields the nonlinear optical response can be enhanced almost 100x by decreasing the beat frequency.
• Moloney, J. V. (2019). Lattice Resonances in Transdimensional WS2 Nanoantenna Arrays. Applied Sciences - Basel, 9, 10.
• Moloney, J. V. (2019). Long-wave Infrared Megafilaments in Air. Nonlinear Optics (NLO)(Optical Society of America, Waikoloa Beach, Hawaii.
• Moloney, J. V. (2019). Microscopic calculation of the optical properties and intrinsic losses in the methylammonium lead iodide perovskite system. Applied Physics Lett. Materials, 011107.
• Moloney, J. V. (2019). Mode-locking in vertical external-cavity surface-emitting lasers with type-II quantum-well configurations. Applied Physics Letters.
• Moloney, J. V. (2019). Non-equilibrium dynamics in the dual-wavelength operation of vertical external-cavity surface-emitting lasers. Optics Express, 5368.
• Moloney, J. V. (2019). Stable 3D FDTD method for arbitrary fully‐electric and magnetic anisotropic Maxwell's equations. International Journal of Numerical Modelling.
• Moloney, J. V., & Babicheva, V. E. (2019). Lattice Zenneck Modes on Subwavelength Antennas. Laser & Photonics Reviews, 13(2), 1800267. doi:10.1002/lpor.201800267
• Moloney, J. V., & Babicheva, V. E. (2019). Lattice Zenneck modes on subwavelength antennas. Laser & Photonics Review 12, 1800267.
• Moloney, J. V., Hader, J., Bannow, L. C., & Koch, S. W. (2019). Microscopic calculation of the optical properties and intrinsic losses in the methylammonium lead iodide perovskite system. APL Materials, 7(1), 011107. doi:10.1063/1.5078791
• Moloney, J. V., Hader, J., Koch, S. W., & Kilen, I. (2019). Mode-locking in vertical external-cavity surface-emitting lasers with type-II quantum-well configurations. Applied Physics Letters, 114(25), 252102. doi:10.1063/1.5098903
• Moloney, J. V., Rosenow, P., Kolesik, M., & Koch, S. W. (2019). Effective nonlinear rovibrational response of water vapor for efficient pulse propagation simulations. Journal Optical Society of America B, 267.
• Nehls, J., Dineen, C., Liu, J., Poole, C., Brio, M., & Moloney, J. V. (2019). Stable 3D FDTD method for arbitrary fully electric and magnetic anisotropic Maxwell's equations. INTERNATIONAL JOURNAL OF NUMERICAL MODELLING-ELECTRONIC NETWORKS DEVICES AND FIELDS, 32(2).
• Panagiotopoulos, P., Kolesik, M., Koch, S. W., Wright, E. M., Tochitsky, S., & Moloney, J. V. (2019). Control of the filament dynamics of 10 mu m pulses via designer pulse trains. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS, 36(10), G33-G39.
• Panagiotopoulos, P., Kolesik, M., Tochitsky, S., Koch, S. W., & Moloney, J. V. (2019). Two-stage filamentation of 10 mu m pulses as a broadband infrared backlighter in the atmosphere. OPTICS LETTERS, 44(12), 3122-3125.
• Rockmore, R., Laurain, A., Moloney, J. V., & Jones, R. J. (2019). Offset-free mid-infrared frequency comb based on a mode-locked semiconductor laser. OPTICS LETTERS, 44(7), 1797-1800.
• Rosenow, P., Kolesik, M., Koch, S. W., & Moloney, J. V. (2019). Effective nonlinear rovibrational response of water vapor for efficient pulse propagation simulations. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS, 36(2), 267-274.
• Rosenow, P., Panagiotopoulos, P., Kolesik, M., Koch, S. W., & Moloney, J. V. (2019). Nonlinear rovibrational response in the propagation of long-wavelength infrared pulses and pulse trains. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS, 36(12), 3457-3463.
• Tochitsky, S., Welch, E., Panagiotopoulos, P., Polyanskiy, M., Pogorelsky, I., Kolesik, M., Koch, S. W., Moloney, J. V., & Joshi, C. (2019). Filamentation of long-wave infrared pulses in the atmosphere [Invited]. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS, 36(10), G40-G51.
• Tochitsky, S., Welch, E., Polyanskiy, M., Pogorelsky, I., Panagiotopoulos, P., Kolesik, M., Wright, E. M., Koch, S. W., Moloney, J. V., Pigeon, J., & Joshi, C. (2019). Megafilament in air formed by self-guided terawatt long-wavelength infrared laser. NATURE PHOTONICS, 13(1), 41-+.
• Wright, E. M., Koch, S. W., Kolesik, M., & Moloney, J. V. (2019). Memory effects in the long-wave infrared avalanche ionization of gases: a review of recent progress. REPORTS ON PROGRESS IN PHYSICS, 82(6).
• Addamane, S., Shima, D., Laurain, A., Chan, H., Balakrishnan, G., & Moloney, J. V. (2018). Degradation mechanism of SESAMs under intense ultrashort pulses in modelocked VECSELs. VERTICAL EXTERNAL CAVITY SURFACE EMITTING LASERS (VECSELS) VIII, 10515.
• Babicheva, V. E., & Moloney, J. V. (2018). Lattice effect influence on the electric and magnetic dipole resonance overlap in a disk array. NANOPHOTONICS, 7(10), 1663-1668.
• Fuchs, C., Brueggemann, A., Weseloh, M. J., Berger, C., Moeller, C., Reinhard, S., Hader, J., Moloney, J. V., Baeumner, A., Koch, S. W., & Stolz, W. (2018). High-temperature operation of electrical injection type-II (GaIn)As/Ga(AsSb)/(GaIn)As "W"-quantum well lasers emitting at 1.3 mu m. SCIENTIFIC REPORTS, 8.
• Fuchs, C., Ludewig, P., Brueggemann, A., Perez, A. R., Weseloh, M. J., Reinhard, S., Hader, J., Moloney, V., Baeumner, A., Koch, S. W., & Stolz, W. (2018). Low-threshold operation of GaAs-based (GaIn)As/Ga(AsSb)/(GaIn)As "W"-quantum well lasers emitting at 1.3 mu m. 2018 IEEE INTERNATIONAL SEMICONDUCTOR LASER CONFERENCE (ISLC), 221-222.
• Hader, J., Badescu, S. C., Bannow, L. C., Moloney, J. V., Johnson, S. R., & Koch, S. W. (2018). Auger losses in dilute InAsBi. APPLIED PHYSICS LETTERS, 112(19).
• Hader, J., Badescu, S. C., Bannow, L. C., Moloney, J. V., Johnson, S. R., & Koch, S. W. (2018). Evaluation of Dilute Bismide Materials for Mid-IR Applications. 2018 IEEE INTERNATIONAL SEMICONDUCTOR LASER CONFERENCE (ISLC), 183-184.
• Hader, J., Badescu, S. C., Bannow, L. C., Moloney, J. V., Johnson, S. R., & Koch, S. W. (2018). Extended band anti-crossing model for dilute bismides. APPLIED PHYSICS LETTERS, 112(6).
• Hofstrand, A., & Moloney, J. V. (2018). Modeling ultrashort electromagnetic pulses with a generalized Kadomtsev-Petviashvili equation. PHYSICA D-NONLINEAR PHENOMENA, 366, 51-58.
• Kilen, I., Koch, S. W., Hader, J., & Moloney, J. V. (2018). Microscopic many-body model for mode-locked and multi-wavelength operation in Vertical External-Cavity Surface-Emitting Lasers. 2018 IEEE INTERNATIONAL SEMICONDUCTOR LASER CONFERENCE (ISLC), 201-202.
• Kilen, I., Koch, S. W., Hader, J., & Moloney, J. V. (2018). VECSEL design for high peak power ultrashort mode-locked operation. APPLIED PHYSICS LETTERS, 112(26).
• Kilen, I., Moloney, J. V., Hader, J., & Koch, S. W. (2018). Influence of Microscopic Many-Body Scattering on the performance of Ultrashort Pulsed and CW Multi-wavelength VECSEL Lasing. VERTICAL EXTERNAL CAVITY SURFACE EMITTING LASERS (VECSELS) VIII, 10515.
• Laurain, A., Kilen, I., Hader, J., Perez, A. R., Ludewig, P., Stolz, W., Addamane, S., Balakrishnan, G., Koch, S. W., & Moloney, J. V. (2018). Modeling and experimental realization of modelocked VECSEL producing high power sub-100 fs pulses. APPLIED PHYSICS LETTERS, 113(12).
• Laurain, A., Rockmore, R., Baker, C. W., Kilen, I., Addamane, S., Balakrishnan, G., Hader, J., Perez, A. R., Stolz, W., Koch, S. W., & Moloney, J. V. (2018). Structure and Cavity Geometry Optimization for Ultrashort and High Power Pulse Generation from a VECSEL. VERTICAL EXTERNAL CAVITY SURFACE EMITTING LASERS (VECSELS) VIII, 10515.
• Laurain, A., Rockmore, R., Kilen, I., Baker, C., Scheller, M., Addamane, S., Balakrishnan, G., Jones, R. J., Koch, S. W., & Moloney, J. V. (2018). VECSEL platform for single/dual frequency CW operation and ultrashort pulse generation. 2018 IEEE INTERNATIONAL SEMICONDUCTOR LASER CONFERENCE (ISLC), 101-102.
• Moloney, J. V., & Babicheva, V. E. (2018). Lattice effect influence on the electric and magnetic dipole resonance overlap in a disk array. Nanophotonics, 7(10), 1663-1668. doi:10.1515/nanoph-2018-0107
• Moloney, J. V., Dineen, C., Nehls, J., Liu, J., Poole, C., & Brio, M. (2018). Stable 3D FDTD method for arbitrary fully electric and magnetic anisotropic Maxwell's equations. International Journal of Numerical Modelling: Electronic Networks, Devices and Fields, 32(2). doi:10.1002/jnm.2521
• Moloney, J. V., Nehls, J., Dineen, C., Liu, J., & Brio, M. (2018). Stable 3D FDTD method for arbitrary fully‐electric and magnetic anisotropic Maxwell's equations. Int J Numer Model.
• Rockmore, R., Baker, C. W., Laurain, A., Wu, T., Jones, R. J., & Moloney, J. V. (2018). Supercontinuum generation and beatnote detection using ultrafast VECSEL seed oscillators. VERTICAL EXTERNAL CAVITY SURFACE EMITTING LASERS (VECSELS) VIII, 10515.
• Rockmore, R., Laurain, A., Moloney, J. V., & Jones, R. J. (2018). VECSEL-Based Offset-Free Frequency Comb in the MIR. 2018 IEEE INTERNATIONAL SEMICONDUCTOR LASER CONFERENCE (ISLC), 203-204.
• Baker, C. W., Scheller, M., Laurain, A., Ruiz-Perez, A., Stolz, W., Addamane, S., Balakrishnan, G., Koch, S. W., Jones, R. J., & Moloney, J. V. (2017). Multi-Angle VECSEL Cavities for Dispersion Control and Peak-Power Scaling. IEEE PHOTONICS TECHNOLOGY LETTERS, 29(3), 326-329.
• Baker, C., Scheller, M., Laurain, A., Yang, H., Perez, A. R., Stolz, W., Addamane, S. J., Balakrishnan, G., Jones, R. J., & Moloney, J. V. (2017). Multi-angle VECSEL cavities for dispersion control and multi-color operation. VERTICAL EXTERNAL CAVITY SURFACE EMITTING LASERS (VECSELS) VII, 10087.
• Bannow, L. C., Badescu, S. C., Hader, J., Moloney, J. V., & Koch, S. W. (2017). Valence band splitting in bulk dilute bismides. APPLIED PHYSICS LETTERS, 111(18).
• Bannow, L. C., Rosenow, P., Springer, P., Fischer, E. W., Hader, J., Moloney, J. V., Tonner, R., & Koch, S. W. (2017). An ab initio based approach to optical properties of semiconductor heterostructures. MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING, 25(6).
• Hader, J., Kilen, I., Koch, S. W., & Moloney, J. V. (2017). Non-equilibrium effects in VECSELs. VERTICAL EXTERNAL CAVITY SURFACE EMITTING LASERS (VECSELS) VII, 10087.
• Hader, J., Scheller, M., Laurain, A., Kilen, I., Baker, C., Moloney, J. V., & Koch, S. W. (2017). Ultrafast non-equilibrium carrier dynamics in semiconductor laser mode-locking. SEMICONDUCTOR SCIENCE AND TECHNOLOGY, 32(1).
• Kilen, I., Koch, S. W., Hader, J., & Moloney, J. V. (2017). Non-equilibrium ultrashort pulse generation strategies in VECSELs. OPTICA, 4(4), 412-417.
• Laurain, A., Marah, D., Rockmore, R., McInerney, J. G., Hader, J., Perez, A. R., Koch, S. W., Stolz, W., & Moloney, J. V. (2017). High power sub-200fs pulse generation from a colliding pulse modelocked VECSEL. VERTICAL EXTERNAL CAVITY SURFACE EMITTING LASERS (VECSELS) VII, 10087.
• Laurain, A., Rockmore, R., Chan, H., Hader, J., Koch, S. W., Perez, A. R., Stolz, W., & Moloney, J. V. (2017). Pulse interactions in a colliding pulse mode-locked vertical external cavity surface emitting laser. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS, 34(2), 329-337.
• Moeller, C., Zhang, F., Fuchs, C., Berger, C., Rehn, A., Perez, A. R., Rahimi-Iman, A., Hader, J., Koch, M., Moloney, J. V., Koch, S. W., & Stolz, W. (2017). Fundamental transverse mode operation of a type-II vertical-external-cavity surfaceemitting laser at 1.2 mu m. ELECTRONICS LETTERS, 53(2), 93-94.
• Moller, C., Fuchs, C., Berger, C., Zhang, F., Rahimi-iman, A., Koch, M., Koch, S. W., Hader, J., Moloney, J. V., Stolz, W., & Perez, A. R. (2017). The development and fundamental analysis of type-II VECSELs at 1.2 μm (Conference Presentation). Proceedings of SPIE, 10087. doi:10.1117/12.2252882
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  Since the invention of VECSELs, vast spectral coverage has been demonstrated with emission wavelengths in the range from the UV to almost the MIR. Accordingly, a great variety of different quantum well and quantum dot gain designs have been applied so far to achieve such versatility. A novel gain design for GaAs based VECSELs emitting at wavelengths >1.2 μm employs type-II quantum wells, which exhibit spatially indirect charge-carrier recombination. The first VECSEL based on such a design has been demonstrated very recently. Our device consists of ten (GaIn)As/Ga(AsSb)/(GaIn)As heterostructures arranged as a resonant periodic gain. We summarize the development of this pioneering structure and discuss the fundamental laser characteristics, such as carrier densities, gain temperatures and slope efficiency. Remarkable output powers up to 4 W are demonstrated in multi-transverse mode operation at 1.2 μm. Also, the performance in TEM00 operation is investigated, with an M 2 < 1.13. One major difference to conventional type-I gain structures is a characteristic blue shift of the material gain. Due to the importance of the detuning in quantum well based surface-emitters, the blue shift has to be considered as a critical designing parameter. Hence, we carry out a detuning study in order to determine an optimal detuning. As an important part of the optimization, the experimental results are compared with fully microscopic simulations.
• Moloney, J. V., Schuh, K., Panagiotopoulos, P., Kolesik, M., & Koch, S. W. (2017). Long Range Robust Multi-Terawatt MWIR and LWIR Atmospheric Light Bullets. ULTRAFAST BANDGAP PHOTONICS II, 10193.
• Scheller, M., Baker, C. W., Koch, S. W., Moloney, J. V., & Jones, R. J. (2017). High Power Dual-Wavelength VECSEL Based on a Multiple Folded Cavity. IEEE PHOTONICS TECHNOLOGY LETTERS, 29(10), 790-793.
• Schuh, K., Kolesik, M., Wright, E. M., Moloney, J. V., & Koch, S. W. (2017). Self-Channeling of High-Power Long-Wave Infrared Pulses in Atomic Gases. PHYSICAL REVIEW LETTERS, 118(6).
• Schuh, K., Panagiotopoulos, P., Kolesik, M., Koch, S. W., & Moloney, J. V. (2017). Multi-terawatt 10 mu m pulse atmospheric delivery over multiple Rayleigh ranges. OPTICS LETTERS, 42(19), 3722-3725.
• Schuh, K., Rosenow, P., Kolesik, M., Wright, E. M., Koch, S. W., & Moloney, J. V. (2017). Nonlinear rovibrational polarization response of water vapor to ultrashort long-wave infrared pulses. PHYSICAL REVIEW A, 96(4).
• Brown, J. M., Jakobsen, P., Bahl, A., Moloney, J. V., & Kolesik, M. (2016). On the convergence of quantum resonant-state expansion. JOURNAL OF MATHEMATICAL PHYSICS, 57(3).
• Fuchs, C., Berger, C., Moeller, C., Weseloh, M., Reinhard, S., Hader, J., Moloney, J. V., Koch, S. W., & Stolz, W. (2016). Electrical injection type-II (GaIn)As/Ga(AsSb)/(GaIn)As single "W'-quantum well laser at 1.2 mu m. ELECTRONICS LETTERS, 52(22), 1875-1876.
• Gbele, K., Laurain, A., Hader, J., Stolz, W., & Moloney, J. V. (2016). Design and Fabrication of Hybrid Metal Semiconductor Mirror for High-Power VECSEL. IEEE PHOTONICS TECHNOLOGY LETTERS, 28(7), 732-735.
• Gies, S., Weseloh, M. J., Fuchs, C., Stolz, W., Hader, J., Moloney, J. V., Koch, S. W., & Heimbrodt, W. (2016). Band offset in (Ga, In)As/Ga(As, Sb) heterostructures. JOURNAL OF APPLIED PHYSICS, 120(20).
• Hader, J., Yang, H. -., Scheller, M., Moloney, J. V., & Koch, S. W. (2016). Microscopic analysis of saturable absorbers: Semiconductor saturable absorber mirrors versus graphene. JOURNAL OF APPLIED PHYSICS, 119(5).
• Huttner, U., Schuh, K., Moloney, J. V., & Koch, S. W. (2016). Similarities and differences between high-harmonic generation in atoms and solids [Invited]. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS, 33(7).
• Kilen, I., Koch, S. W., Hader, J., & Moloney, J. V. (2016). Fully microscopic modeling of mode locking in microcavity lasers. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS, 33(1), 75-80.
• Kilen, I., Koch, S. W., Hader, J., & Moloney, J. V. (2016). Modeling of ultrashort pulse generation in mode-locked VECSELs. PHYSICS AND SIMULATION OF OPTOELECTRONIC DEVICES XXIV, 9742.
• Lammers, C., Stein, M., Berger, C., Moeller, C., Fuchs, C., Perez, A. R., Rahimi-Iman, A., Hader, J., Moloney, J. V., Stolz, W., Koch, S. W., & Koch, M. (2016). Gain spectroscopy of a type-II VECSEL chip. APPLIED PHYSICS LETTERS, 109(23).
• Laurain, A., Gbele, K., Hader, J., Stolz, W., Moloney, J. V., Perez, A. R., & Koch, S. W. (2016). Hybrid metal-semiconductor mirror for high power VECSEL. Proceedings of SPIE, 9734. doi:10.1117/12.2212937
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  We demonstrate a low thermal impedance hybrid mirror VECSEL. We used only 14 pairs of AlGaAs/AlAs, transparent at the pump wavelength, and we used a patterned mask to deposit pure gold on areas of the chip to be pumped, and Ti/Au on other area to circumvent the poor adhesion of gold on GaAs. A higher gain is observed on an area metallized with pure gold and an output power of 4W was obtained, showing the effectiveness of the metallic mirror and validating the bonding quality. Chip processing and laser characteristics are studied in detail and compared to simulations.
• Laurain, A., Marah, D., Rockmore, R., McInerney, J., Hader, J., Perez, A. R., Stolz, W., & Moloney, J. V. (2016). Colliding pulse mode locking of vertical-external-cavity surface-emitting laser. OPTICA, 3(7), 781-784.
• Marah, D., Laurain, A., Stolz, W., Perez, A. R., Moloney, J. V., Mcinerney, J. G., & Koch, S. W. (2016). Colliding pulse mode-locked VECSEL. Proceedings of SPIE, 9734. doi:10.1117/12.2212902
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  Recent development of high power femtosecond pulse modelocked VECSEL with gigahertz pulse repetition rates sparked an increased interest from the scientific community due to the broad field of applications for such sources, such as frequency metrology, high-speed optical communication systems or high-resolution optical sampling. To the best of our knowledge, we report for the first time a colliding pulse modelocked VECSEL, where the VECSEL gain medium and a semiconductor saturable absorber (SESAM) are placed inside a ring cavity. This cavity geometry provides both a practical and an efficient way to get optimum performance from a modelocked laser system. The two counter propagating pulses in our ring cavity synchronize in the SESAM because the minimum energy is lost when they saturate the absorber together. This stronger saturation of the absorber increases the stability of the modelocking and reduces the overall losses of the laser for a given intra-cavity fluence, leading to a lower modelocking threshold. This also allows the generation of fundamental modelocking at a relatively low repetition rate (
• Moeller, C., Fuchs, C., Berger, C., Perez, A. R., Koch, M., Hader, J., Moloney, J. V., Koch, S. W., & Stolz, W. (2016). Type-II vertical-external-cavity surface-emitting laser with Watt level output powers at 1.2 mu m. APPLIED PHYSICS LETTERS, 108(7).
• Moller, C., Berger, C., Fuchs, C., Koch, S. W., Hader, J., Moloney, J. V., Stolz, W., & Perez, A. R. (2016). 1.2μm emitting VECSEL based on type-II aligned QWs. Proceedings of SPIE, 9734. doi:10.1117/12.2212438
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  Since the invention of VECSELs, their great spectral coverage has been demonstrated and emission wavelengths in the range from UV to almost MIR have been achieved. However, in the infrared regime the laser performance is affected by Auger losses which become significant at large quantum defects. In order to reduce the Auger losses and to develop more efficient devices in the IR, type-II aligned QWs have been suggested as alternative gain medium for semiconductor lasers.
• Moloney, J. V., Bahl, A., Brown, J. M., Jakobsen, P., & Kolesik, M. (2016). On the convergence of quantum resonant-state expansion. Journal of Mathematical Physics, 57(3), 032105. doi:10.1063/1.4944625
• Moloney, J. V., Gies, S., Weseloh, M. J., Fuchs, C., Stolz, W., Hader, J., Koch, S. W., & Heimbrodt, W. (2016). Band offset in (Ga, In)As/Ga(As, Sb) heterostructures. Journal of Applied Physics, 120(20), 204303. doi:10.1063/1.4968541
• Moloney, J. V., Hader, J., Yang, H. J., Scheller, M., & Koch, S. W. (2016). Microscopic Analysis of Saturable Absorbers; SESAM versus Graphene. Journal of Applied Phyics, 119, 053102.
• Moloney, J. V., Kilen, I., Hader, J., & Koch, S. W. (2016). Influence of kinetic hole filling on the stability of mode-locked semiconductor disk lasers. Proceedings of SPIE, 9734. doi:10.1117/12.2213600
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  Microscopic many-body theory is employed to analyze the mode-locking dynamics of a vertical external-cavity surface-emitting laser with a saturable absorber mirror. The quantum-wells are treated microscopically through the semiconductor Bloch equations and the light field using Maxwell's equations. Higher order correlation effects such as polarization dephasing and carrier relaxation at the second Born level are included and also approximated using effective rates fitted to second-Born-Markov evaluations. The theory is evaluated numerically for vertical external cavity surface emitting lasers with resonant periodic gain media. For given gain, the influence of the loss conditions on the very-short pulse generation in the range above 100 fs is analyzed. Optimized operational parameters are identified. Additionally, the fully microscopic theory at the second Born level is used to carrier out a pump-probe study of the carrier recovery in individual critical components of the VECSEL cavity such as the VECSEL chip itself and semiconductor or graphene saturable absorber mirrors.
• Moloney, J. V., Kilen, I., Koch, S. W., & Hader, J. (2016). Fully microscopic modeling of mode-locking in micro cavity lasers. Journal of the Optical Society of America B, 33, 75.
• Moloney, J. V., Lammers, C., Stein, M., Berger, C., Möller, C., Fuchs, C., Ruiz Perez, A., Rahimi-Iman, A., Hader, J., Stolz, W., Koch, S. W., & Koch, M. (2016). Gain spectroscopy of a type-II VECSEL chip. Applied Physics Letters, 109(23), 232107. doi:10.1063/1.4971333
• Moloney, J. V., Schuh, K., & Koch, S. W. (2016). Interaction-induced nonlinear refractive-index reduction of gases in the midinfrared regime. Physical Review E, 93, C22.
• Moloney, J. V., Yang, H., Hader, J., Scheller, M., & Koch, S. W. (2016). Microscopic analysis of saturable absorbers: Semiconductor saturable absorber mirrors versus graphene. Journal of Applied Physics, 119(5), 053102. doi:10.1063/1.4941350
• Panagiotopoulos, P., Kolesik, M., & Moloney, J. V. (2016). Exploring the limits to energy scaling and distant-target delivery of high-intensity midinfrared pulses. PHYSICAL REVIEW A, 94(3).
• Panagiotopoulos, P., Schuh, K., Kolesik, M., & Moloney, J. V. (2016). Simulations of 10 mu m filaments in a realistically modeled atmosphere. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS, 33(10), 2154-2161.
• Scheller, M., Baker, C. W., Koch, S. W., & Moloney, J. V. (2016). Dual-Wavelength Passively Mode-Locked Semiconductor Disk Laser. IEEE PHOTONICS TECHNOLOGY LETTERS, 128(12), 1325-1327.
• Schuh, K., Moloney, J. V., & Koch, S. W. (2016). Interaction-induced nonlinear refractive-index reduction of gases in the midinfrared regime. PHYSICAL REVIEW E, 93(1).
• Springer, P., Gies, S., Hens, P., Fuchs, C., Han, H., Hader, J., Moloney, J. V., Stolz, W., Volz, K., Koch, S. W., & Heimbrodt, W. (2016). Charge transfer luminescence in (GaIn)As/GaAs/Ga(NAs) double quantum wells. JOURNAL OF LUMINESCENCE, 175, 255-259.
• Al Nakdali, D., Shakfa, M. K., Heinen, B., Kunert, B., Stolz, W., Koch, S. W., Hader, J., Moloney, J. V., Rahimi-Iman, A., & Koch, M. (2015). Analysis of optical scattering losses in vertical-external-cavity surface-emitting lasers. APPLIED PHYSICS B-LASERS AND OPTICS, 120(1), 41-46.
• Badescu, S. C., Grupen, M. E., Hader, J., Moloney, J. V., & Koch, S. W. (2015). First-Principle Tight Binding-Like Parametrizations of GaAs$_{\mathrm{1-x}}$Bi$_{\mathrm{x}}$ and InAs$_{\mathrm{1-x}}$Bi$_{\mathrm{x}}$ Electronic Structures. Bulletin of the American Physical Society.
• Baker, C., Scheller, M., Koch, S. W., Perez, A. R., Stolz, W., Jones, R. J., & Moloney, J. V. (2015). In situ probing of mode-locked vertical-external-cavity-surface-emitting lasers. OPTICS LETTERS, 40(23), 5459-5462.
• Berger, C., Moeller, C., Hens, P., Fuchs, C., Stolz, W., Koch, S. W., Perez, A. R., Hader, J., & Moloney, J. V. (2015). Novel type-II material system for laser applications in the near-infrared regime. AIP ADVANCES, 5(4).
• Born, N., Al-Naib, I., Jansen, C., Singh, R., Moloney, J. V., Scheller, M., & Koch, M. (2015). Terahertz Metamaterials with Ultrahigh Angular Sensitivity. ADVANCED OPTICAL MATERIALS, 3(5), 642-645.
• Bottge, C. N., Hader, J., Kilen, I., Koch, S. W., & Moloney, J. V. (2015). Influence of non-equilibrium carrier dynamics on pulse amplification in semiconductor gain media. Proceedings of SPIE, 9349. doi:10.1117/12.2080140
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  The influence of non-equilibrium carrier dynamics on pulse propagation through inverted semiconductor gain media is investigated. For this purpose, a fully microscopic many-body model is coupled to a Maxwell solver, allowing for a self-consistent investigation of the light–matter-coupling and carrier dynamics, the optical response of the laser and absorber in the multiple-quantum-well medium, and the modification of the light field through the resulting optical polarization. The influence of the intra-pulse dynamics on the magnitude and spectral dependence of pulse amplification for single pulses passing through inverted quantum-well media is identified. In this connection, the pulse-induced non-equilibrium deviations of the carrier distributions, the kinetic-hole filling kinetics in the gain medium, and the saturable-absorber-relaxation dynamics are scrutinized. While pulses shorter than about 100 fs are found to be rather unaffected by the carrier-relaxation dynamics, the pump-related dynamics become prominent for pulses in the multi-picosecond range leading to significant amplification.
• Gies, S., Kruska, C., Berger, C., Hens, P., Fuchs, C., Perez, A. R., Rosemann, N. W., Veletas, J., Chatterjee, S., Stolz, W., Koch, S. W., Hader, J., Moloney, J. V., & Heimbrodt, W. (2015). Excitonic transitions in highly efficient (GaIn)As/Ga(AsSb) type-II quantum-well structures. APPLIED PHYSICS LETTERS, 107(18).
• Hader, J., Moloney, J. V., & Koch, S. W. (2015). Optical excitation dependent emission properties of InGaN quantum wells. JOURNAL OF COMPUTATIONAL ELECTRONICS, 14(2), 425-431.
• Moloney, J. V., Born, N., Al-Naib, I., Jansen, C., Singh, R., Scheller, M., & Koch, M. (2015). Terahertz Metamaterials with Ultrahigh Angular Sensitivity. Advanced Optical Materials, 3(5), 642-645. doi:10.1002/adom.201400469
• Moloney, J. V., Gbele, K., Laurain, A., Hader, J., & Stolz, W. (2015). Design and fabrication of hybrid metal semiconductor mirror for high power VECSEL. Photonics Technology Letters, IEEE, 28(Issue 7), 732 - 735. doi:10.1109/LPT.2015.2507059
• Panagiotopoulos, P., Whalen, P., Kolesik, M., & Moloney, J. V. (2015). Carrier field shock formation of long-wavelength femtosecond pulses in single-crystal diamond and air. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS, 32(8), 1718-1730.
• Panagiotopoulos, P., Whalen, P., Kolesik, M., & Moloney, J. V. (2015). Super high power mid-infrared femtosecond light bullet. NATURE PHOTONICS, 9(8), 543-+.
• Schuh, K., Hader, J., Moloney, J. V., & Koch, S. W. (2015). Influence of optical and interaction-induced dephasing effects on the short-pulse ionization of atomic gases. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS, 32(7), 1442-1449.
• Whalen, P., Brio, M., & Moloney, J. V. (2015). Exponential time-differencing with embedded Runge-Kutta adaptive step control. JOURNAL OF COMPUTATIONAL PHYSICS, 280, 579-601.
• B\"ottge, C., Hader, J., Kilen, I., Moloney, J., & Koch, S. (2014). Ultrafast pulse amplification in mode-locked vertical external-cavity surface-emitting lasers. Applied Physics Letters, 105(26), 261105.
• Born, N., Scheller, M., Koch, M., & Moloney, J. V. (2014). Cavity enhanced terahertz modulation. Applied Physics Letters, 104(10).
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  Abstract: We present a versatile concept for all optical terahertz (THz) amplitude modulators based on a Fabry-Pérot semiconductor cavity design. Employing the high reflectivity of two parallel meta-surfaces allows for trapping selected THz photons within the cavity and thus only a weak optical modulation of the semiconductor absorbance is required to significantly damp the field within the cavity. The optical switching yields to modulation depths of more than 90% with insertion efficiencies of 80%. © 2014 AIP Publishing LLC.
• Breddermann, B., B\"aumner, A., Koch, S., Ludewig, P., Stolz, W., Volz, K., Hader, J., Moloney, J., Broderick, C., & others, . (2014). Luminescence properties of dilute bismide systems. Journal of Luminescence, 154, 95--98.
• Gemmer, J. A., Venkataramani, S. C., Durfee, C. G., & Moloney, J. V. (2014). Optical beam shaping and diffraction free waves: A variational approach. PHYSICA D-NONLINEAR PHENOMENA, 283, 15-28.
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  We investigate the problem of shaping radially symmetric annular beams into desired intensity patterns along the optical axis. Within the Fresnel approximation, we show that this problem can be expressed in a variational form equivalent to the one arising in phase retrieval. Using the uncertainty principle we prove various rigorous lower bounds on the functional; these lower bounds estimate the L-2 error for the beam shaping problem in terms of the design parameters. We also use the method of stationary phase to construct a natural ansatz for a minimizer in the short wavelength limit. We illustrate the implications of our results by applying the method of stationary phase coupled with the Gerchberg-Saxton algorithm to beam shaping problems arising in the remote delivery of beams and pulses. (C) 2014 Elsevier B.V. All rights reserved.
• Hader, J., Moloney, J. V., & Koch, S. W. (2014). Microscopic analysis of non-equilibrium dynamics in the semiconductor-laser gain medium. APPLIED PHYSICS LETTERS, 104(15).
• Hader, J., Moloney, J., & Koch, S. (2014). Microscopic analysis of non-equilibrium dynamics in the semiconductor-laser gain medium. Applied Physics Letters, 104(15), 151111.
• Kolesik, M., & Moloney, J. V. (2014). Modeling and simulation techniques in extreme nonlinear optics of gaseous and condensed media. Reports on Progress in Physics, 77(1).
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  Abstract: Computer simulation techniques for extreme nonlinear optics are reviewed with emphasis on the high light-intensity regimes in which both bound and freed electronic states contribute to the medium response and thus affect the optical pulse dynamics. The first part concentrates on the optical pulse propagation modeling, and provides a classification of various approaches to optical-field evolution equations. Light-matter interaction models are reviewed in the second part, which concentrates on methods that can be integrated with time- and space-resolved simulations encompassing realistic experimental scenarios. © 2014 IOP Publishing Ltd.
• Kolesik, M., Brown, J., Moloney, J., & Faccio, D. (2014). History-dependent effects in subcycle-waveform strong-field ionization. Physical Review A, 90(3), 033414.
• Kolesik, M., Brown, J., Teleki, A., Jakobsen, P., Moloney, J., & Wright, E. (2014). Metastable electronic states and nonlinear response for high-intensity optical pulses. Optica, 1(5), 323--331.
• Laurain, A., Hader, J., Koch, S. W., Stolz, W., & Moloney, J. V. (2014). Intensity and frequency noise properties of multi-Watt single frequency VECSEL with and without active stabilization. Proceedings of SPIE, 8966. doi:10.1117/12.2037976
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  ABSTRACT We demonstrate the highest free running single frequency power from a single chip VECSEL reported to date,with more than 15W in continuous operation at room temperature. The GaAs-based structure presents anemission wavelength of 1020nm and a tuning range > 15nm, with a continuous tunability of 9GHz. The TEM 00 output beam exhibits very low transverse phase ”uctuations across the entire mode, leading to a beam qualityM 2 < 1.2. To identify and reduce the dierent sources of noise, the relative intensity noise and frequency noisespectral density are investigated and the intensity and th e frequency of the laser were independently stabilized.The laser frequency is controlledand tuned varyingthe cavitylength using a high bandwidth piezoelectric elementwhile intensity ”uctuations are reduced by varying the pump intensity. Intrinsic and stabilized frequency andintensity noise are compared.Keywords: VECSEL, OPSL, semiconductor, high power, narrow linewidth, stabilization, optical noise.
• Laurain, A., Mart, C., Hader, J., Moloney, J. V., Kunert, B., & Stolz, W. (2014). 15 W single frequency optically pumped semiconductor laser with sub-megahertz linewidth. IEEE Photonics Technology Letters, 26(2), 131-133.
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  Abstract: We report on a single frequency optically pumped semiconductor laser exhibiting an output power of 15 W in continuous wave operation. The GaAs-based structure presents an emission wavelength of 1020 nm and a tuning range > 15 nm, with a continuous tunability of 9 GHz. The TEM00 output beam exhibits very low transverse phase fluctuations across the entire mode, leading to a beam quality M2
• Laurain, A., Mart, C., Hader, J., Moloney, J. V., Kunert, B., & Stolz, W. (2014). Optical noise of stabilized high-power single frequency optically pumped semiconductor laser. OPTICS LETTERS, 39(6), 1573-1576.
• Laurain, A., Mart, C., Hader, J., Moloney, J. V., Kunert, B., & Stolz, W. (2014). Optical noise of stabilized high-power single frequency optically pumped semiconductor laser. Optics Letters, 39(6), 1573-1576.
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  Abstract: We present a study of an actively stabilized optically pumped semiconductor laser operating single frequency at a wavelength of 1015 nm. In free running operation, the laser exhibits a single frequency output power of 15Wwith a linewidth of 995 kHz for a sampling time of 1 s. The intensity and the frequency of the laser were independently stabilized to reach a laser linewidth of only 4 kHz for the same sampling time. To identify and reduce the different sources of noise, the relative intensity noise and frequency noise spectral density are investigated under various conditions. © 2014 Optical Society of America.
• Liu, J., Brio, M., & Moloney, J. V. (2014). An overlapping Yee finite-difference time-domain method for material interfaces between anisotropic dielectrics and general dispersive or perfect electric conductor media. International Journal of Numerical Modelling: Electronic Networks, Devices and Fields, 27(1), 22--33.
• Lu, C. A., Roach, W. P., Balakrishnan, G., Albrecht, A. R., Moloney, J. V., & Glebov, L. B. (2014). Beam combination of multiple vertical external cavity surface emitting lasers via volume Bragg gratings. Proceedings of SPIE, 8966. doi:10.1117/12.2039666
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  We present an experimental study on beam combining techniques with multiple vertical external cavity surface emitting lasers (VECSELs) using volume Bragg gratings (VBGs). The specially designed holographic gratings introduce frequency specific feedback for the near infrared wavelength VECSELs to achieve both spectral linewidth narrowing and beam combination effects. For coherent addition, we obtained >3W output power with 8% slope efficiency in a coherent power scaling cavity scheme. In the multiplexed VBGs (MVBGs) wavelength beam combining compound cavity scheme, we measured >6W combined output with nearly 100% combining efficiency. Both beam combining/power scaling schemes produced spectrally narrowed and near diffraction limited outputs.
• Moloney, J. V. (2014). Influence of many-body interactions during the ionization of gases by short intense optical pulses. Physical Review E.
• Moloney, J. V. (2014). Quantum theory of terahertz emission due to ultrashort pulse ionization of gases. Physical Review E, 88(6), 063102.
• Moloney, J. V. (2014). Raman conversion in intense femtosecond Bessel beams in air. Physical Review A.
• Moloney, J. V. (2014). Transformation optics based local mesh refinement for solving Maxwell's equations. Journal of Computational Physics.
• Moloney, J. V. (2014). Ultrafast nonequilibrium carrier dynamics in semiconductor laser mode locking. Optica, 1 (4), 195-197.
• Moloney, J. V., Kilen, I., Baumner, A., Scheller, M., & Koch, S. W. (2014). Nonequilibrium and thermal effects in modelocked VECSELs. Optics Express, 22(6), 6422-6427.
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  Abstract: Ultrafast femtosecond timescale dynamics in Vertical External Cavity Surface Emitting Lasers (VECSELs) have recently been employed to achieve record average power and duration mode-locked pulses by employing different types of saturable absorbers and Kerr Lens elements. Microscopic many-body dynamics are expected to dominate when attempting to push pulse durations below 100 fs. We present a preliminary microscopic simulation of ultrafast mode-locking in order to expose the role of hot carrier distributions in establishing ultrafast mode-locking. © 2014 Optical Society of America.
• Scheller, M., Mills, M. S., Miri, M., Cheng, W., Moloney, J. V., Kolesik, M., Polynkin, P., & Christodoulides, D. N. (2014). Externally refuelled optical filaments. Nature Photonics, 8(4), 297-301.
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  Abstract: Plasma channels produced in air through femtosecond laser filamentation hold great promise for a number of applications, including remote sensing, attosecond physics and spectroscopy, channelling microwaves and lightning protection. In such settings, extended filaments are desirable, yet their longitudinal span is limited by dissipative processes. Although various techniques aiming to prolong this process have been explored, the substantial extension of optical filaments remains a challenge. Here, we experimentally demonstrate that the natural range of a plasma column can be enhanced by at least an order of magnitude when the filament is prudently accompanied by an auxiliary beam. In this arrangement, the secondary low-intensity 'dressing' beam propagates linearly and acts as a distributed energy reservoir, continuously refuelling the optical filament. Our approach offers an efficient and viable route towards the generation of extended light strings in air without inducing premature wave collapse or an undesirable beam break-up into multiple filaments. © 2014 Macmillan Publishers Limited. All rights reserved.
• Scheller, M., Paul, J. R., Laurain, A., Young, A., Koch, S. W., & Moloney, J. V. (2014). Terahertz generation by difference frequency conversion of two single-frequency VECSELs in an external resonance cavity. Proceedings of SPIE, 8966. doi:10.1117/12.2040399
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  We demonstrate a continuous wave, single frequency terahertz (THz) source based on parametric difference frequency generation within a nonlinear crystal located in an optical enhancement cavity. Two single-frequency VECSELs with emission wavelengths spaced by 6.8 nm are phase locked to the external cavity and are used as pump sources for the nonlinear down conversion. The emitting THz radiation is centered at 1.9 THz and has a linewidth of less than 100 kHz. The output power of the source exceeds 100 μW. We show that the THz source can be used as local oscillator to drive a receiver used in astronomy applications.
• Schuh, K., Kolesik, M., Wright, E., & Moloney, J. (2014). Simple model for the nonlinear optical response of gases in the transparency region. Optics letters, 39(17), 5086--5089.
• Whalen, P., Panagiotopoulos, P., Kolesik, M., & Moloney, J. V. (2014). Extreme carrier shocking of intense long-wavelength pulses. Physical Review A - Atomic, Molecular, and Optical Physics, 89(2).
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  Abstract: We predict a paradigm shift in the nonlinear physics associated with ultrashort long-wavelength pulse propagation in gaseous and condensed media. Optical carrier shock formation, which profoundly modifies the underlying optical wave form, emerges prior to the onset of the well-known self-focusing collapse singularity. The canonical description of pulse propagation in this regime, where all nonlinear envelope descriptions fail, is identified as the full field carrier resolved modified Kadomtsev-Petviashili (MKP) equation. © 2014 American Physical Society.
• Ahirwar, P., Rotter, T. J., Shima, D., Jahan, N. A., Clark, S. P., Addamane, S. J., Balakrishnan, G., Laurain, A., Hader, J., Lai, Y., & others, . (2013). Growth and Optimization of 2-$\mu$m InGaSb/AlGaSb Quantum-Well-Based VECSELs on GaAs/AlGaAs DBRs. IEEE Journal of Selected Topics in Quantum Electronics, 19(4), 1700611.
• Ahirwar, P., Rotter, T. J., Shima, D., Jahan, N. A., Clark, S. P., Addamane, S. J., Balakrishnan, G., Laurain, A., Hader, J., Lai, Y., Moloney, J. V., Suemune, I., & Bedford, R. G. (2013). Growth and optimization of 2-μm InGaSb/AlGaSb quantum-well-based VECSELs on GaAs/AlGaAs DBRs. IEEE Journal on Selected Topics in Quantum Electronics, 19(4).
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  Abstract: We report the growth of optically pumped vertical-external-cavity surface-emitting lasers (VECSELs) based on InGaSb/AlGaSb quantum wells grown on GaAs/AlGaAs distri-buted Bragg reflectors (DBRs). The 7.78% lattice mismatch between GaSb and GaAs is accommodated by an array of 90° misfit dislocations at the interface. This results in spontaneous relaxation of the GaSb epilayer and also significantly reduces the threading dislocation density. The VECSELs are operated in both pulsed (with 340-W peak output power) and continuous wave mode (with 0.12-W peak output power). We investigate the effects of the GaSb/GaAs interface by comparing the lattice mismatched III-Sb VECSEL grown on GaAs/AlGaAs DBRs to a lattice matched III-Sb VECSEL grown on GaSb/AlAsSb DBRs. The lattice matched VECSEL outperforms the lattice mismatched VECSEL in terms of threshold pump density, efficiency, and maximum continuous-wave output power. This can be attributed to the presence of threading dislocations throughout the active region of the mismatched VECSEL, which is confirmed by cross-sectional transmission electron microscopy. The optical properties of the III-Sb active regions are characterized by time-resolved photoluminescence, which can be used to optimize the IMF interface. © 1995-2012 IEEE.
• Chernikov, A., Wichmann, M., Herrmann, J., Heinen, B., Shakfa, M. K., Chatterjee, S., Koch, S. W., Kunert, B., Stolz, W., Wang, T., & others, . (2013). In situ spectroscopy of high-power vertical-external-cavity surface-emitting lasers. physica status solidi (b), 250(9), 1781--1784.
• Chernikov, A., Wichmann, M., Herrmann, J., Heinen, B., Shakfa, M. K., Chatterjee, S., Koch, S. W., Kunert, B., Stolz, W., Wang, T., Kaneda, Y., Scheller, M., Yarborough, M. J., Hader, J., Moloney, J. V., & Koch, M. (2013). In situ spectroscopy of high-power vertical-external-cavity surface-emitting lasers. Physica Status Solidi (B) Basic Research, 250(9), 1781-1784.
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  Abstract: Spectroscopic techniques for an in situ analysis of vertical-external-cavity surface-emitting lasers are presented and exemplary results are discussed. Spatially resolved photoluminescence is shown to provide access to the temperature distribution inside the active area of the laser chip. Both the shape and the size of the pump spot are found to strongly influence the thermal properties and the output power of the device. In addition, the temporal stability of a laser emitting at two distinct wavelengths is studied using single-shot streak-camera measurements. The collected data is evaluated via quantitative statistical analysis schemes identifying stable and unstable regimes of operation. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
• Durfee, C. G., Gemmer, J., & Moloney, J. V. (2013). Phase-only shaping algorithm for Gaussian-apodized Bessel beams. Optics Express, 21(13), 15777-15786.
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  PMID: 23842364;Abstract: Gaussian-apodized Bessel beams can be used to create a Bessel-like axial line focus at a distance from the focusing lens. For many applications it is desirable to create an axial intensity profile that is uniform along the Bessel zone. In this article, we show that this can be accomplished through phase-only shaping of the wavefront in the far field where the beam has an annular ring structure with a Gaussian cross section. We use a one-dimensional transform to map the radial input field to the axial Bessel field and then optimized the axial intensity with a Gerchberg-Saxton algorithm. By separating out the quadratic portion of the shaping phase the algorithm converges more rapidly. © 2013 Optical Society of America.
• Durfee, C. G., Gemmer, J., & Moloney, J. V. (2013). Phase-only shaping algorithm for Gaussian-apodized Bessel beams. Optics express, 21(13), 15777--15786.
• Gemmer, J. A., Venkataramani, S. C., Durfee, C. G., & Moloney, J. V. (2013). Optical beam shaping and diffraction free waves: a variational approach. arXiv preprint arXiv:1307.6289.
• Graf, T., Moloney, J., & Venkataramani, S. (2013). Asymptotic analysis of weakly nonlinear Bessel--Gau\ss beams. Physica D: Nonlinear Phenomena, 243(1), 32--44.
• Hader, J., Wang, T. -., Moloney, J. V., Heinen, B., Koch, M., Koch, S. W., Kunert, B., & Stolz, W. (2013). On the measurement of the thermal impedance in vertical-external-cavity surface-emitting lasers. Journal of Applied Physics, 113(15).
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  Abstract: A detailed and systematic analysis of the loss mechanisms in vertical-external-cavity surface-emitting lasers is presented with the goal to correctly determine the amount of pump power that is converted to heat. With this input, the accuracy of a recently proposed method for measuring the thermal impedance based on roll-over characteristics is shown to be very high for devices with and without dielectric coating. Potential errors arising from non-heating losses can be determined by performing experiments with different out-coupling mirrors. © 2013 AIP Publishing LLC.
• Hader, J., Wang, T., Moloney, J., Heinen, B., Koch, M., Koch, S., Kunert, B., & Stolz, W. (2013). On the measurement of the thermal impedance in vertical-external-cavity surface-emitting lasers. Journal of Applied Physics, 113(15), 153102.
• Laurain, A., Scheller, M., Hader, J., Moloney, J. V., Heinen, B., Kunert, B., Stolz, W., & Wang, T. L. (2013). Recent advances in power scaling of high-power optically-pumped semiconductor lasers for ultrashort pulse generation and continuous wave single frequency operation. Proceedings of SPIE, 8733. doi:10.1117/12.2018310
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  We report on our research in power scaling VECSEL around 1 μm to exceed 100W per chip. Recently, we have utilized these optimized VECSEL chips to achieve a new record for a mode-locked VECSEL. The output power of the laser was 3.4W. This corresponds to a pulse energy of 7.5nJ and a pulse peak power of 13.3kW. Both are record values for a semiconductor laser in the femtosecond regime. These optimized structures have also been used to demonstrate high power operation with a highly coherent TEM00 mode and to demonstrate a record single frequency output power of 15W.
• Moloney, J. V., Brio, M., & Liu, J. (2013). An overlapping Yee finite-difference time-domain method for material interfaces between anisotropic dielectrics and general dispersive or perfect electric conductor media: AN OVERLAPPING YEE FDTD METHOD FOR MATERIAL INTERFACES. International Journal of Numerical Modelling: Electronic Networks, Devices and Fields, 27(1), 22-33. doi:10.1002/jnm.1887
• Moloney, J. V., Kaneda, Y., Chernikov, A., Wichmann, M., Herrmann, J., Heinen, B., Shakfa, M. K., Chatterjee, S., Koch, S. W., Kunert, B., Stolz, W., Wang, T., Scheller, M., Yarborough, M. J., Hader, J., & Koch, M. (2013). In situ spectroscopy of high-power vertical-external-cavity surface-emitting lasers: In situ spectroscopy of high-power vertical-external-cavity surface-emitting lasers. physica status solidi (b), 250(9), 1781-1784. doi:10.1002/pssb.201200696
• Pasenow, B., Dineen, C., Hader, J., Brio, M., Moloney, J., Koch, S., Chen, S., Becker, A., & Jaro\'n-Becker, A. (2013). Anisotropic terahertz response from a strong-field ionized electron-ion plasma. Physical Review E, 87(3), 033106.
• Paul, J. R., Scheller, M., Laurain, A., Young, A., Koch, S. W., & Moloney, J. (2013). Narrow linewidth single-frequency terahertz source based on difference frequency generation of vertical-external-cavity source-emitting lasers in an external resonance cavity. Optics Letters, 38(18), 3654-3657.
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  PMID: 24104838;Abstract: We demonstrate a continuous wave, single-frequency terahertz (THz) source emitting 1.9 THz. The linewidth is less than 100 kHz and the generated THz output power exceeds 100 μW. The THz source is based on parametric difference frequency generation within a nonlinear crystal located in an optical enhancement cavity. Two single-frequency vertical-external-cavity source-emitting lasers with emission wavelengths spaced by 6.8 nm are phase locked to the external cavity and provide pump photons for the nonlinear downconversion. It is demonstrated that the THz source can be used as a local oscillator to drive a receiver used in astronomy applications. © 2013 Optical Society of America.
• Paul, J. R., Scheller, M., Laurain, A., Young, A., Koch, S. W., & Moloney, J. (2013). Narrow linewidth single-frequency terahertz source based on difference frequency generation of vertical-external-cavity source-emitting lasers in an external resonance cavity. Optics letters, 38(18), 3654--3657.
• Polynkin, P., Ament, C., & Moloney, J. (2013). Self-focusing of ultraintense femtosecond optical vortices in air. Physical review letters, 111(2), 023901.
• Polynkin, P., Ament, C., & Moloney, J. V. (2013). Self-focusing of ultraintense femtosecond optical vortices in air. Physical Review Letters, 111(2).
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  Abstract: Our experiments show that the critical power for self-focusing collapse of femtosecond vortex beams in air is significantly higher than that of a flattop beam and grows approximately linearly with the vortex order. With less than 10% of initial transverse intensity modulation of the beam profiles, the dominant mode of self-focusing collapse is the azimuthal breakup of the vortex rings into individual filaments, the number of which grows with the input beam power. The generated bottlelike distributions of plasma filaments rotate on propagation in the direction determined by the sense of vorticity. © 2013 American Physical Society.
• Scheller, M., Laurain, A., Koch, S. W., & Moloney, J. V. (2013). Passively mode-locked femtosecond VECSELs with high average output power. Proceedings of SPIE, 8606. doi:10.1117/12.2003596
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  The broad gain-bandwidth and the high output powers make vertical-external-cavity surface-emitting lasers (VECSELs) promising candidates as femtosecond laser sources. Besides an effective design of the gain structure, the major challenges for high power VECSELs are the thermal management of the chips as well as the homogeneity of the epitaxial growth. In this work, we present results of passively mode-locking of our highly efficient VECSELs and demonstrate femtosecond operation with record output powers and pulse energies. At a repetition rate of 1.7 GHz, we achieved nearly transform-limited pulses with 682 fs duration and an average output power exceeding 5 W.
• Schuh, K., Scheller, M., Hader, J., Moloney, J. V., & Koch, S. W. (2013). Quantum theory of terahertz emission due to ultrashort pulse ionization of gases. Physical Review E - Statistical, Nonlinear, and Soft Matter Physics, 88(6).
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  Abstract: A microscopic model is developed to analyze terahertz (THz) emission after ultrashort one- and two-color laser-pulse excitations of an atomic gas. Optical Bloch equations are derived to describe the pulse-induced ionization in the many-atom system including the Coulombic scattering of the ionized electrons. The model captures the continuous transition between the tunneling and the multiphoton ionization regimes. Numerical evaluations for a wide range of pulse configurations identify optimized excitation conditions for strong THz emission. © 2013 American Physical Society.
• Schuh, K., Scheller, M., Hader, J., Moloney, J., & Koch, S. (2013). Quantum theory of terahertz emission due to ultrashort pulse ionization of gases. Physical Review E, 88(6), 063102.
• Wichmann, M., Shakfa, M. K., Zhang, F., Heinen, B., Scheller, M., Rahimi-Iman, A., Stolz, W., Moloney, J. V., Koch, S. W., & Koch, M. (2013). Evolution of Multi-Mode operation in Verticalexternal-Cavity Surface-Emitting lasers. Optics Express, 21(26), 31940-31950.
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  Abstract: The longitudinal multi-mode emission in a vertical-externalcavity surface-emitting laser is investigated using both single shot streak camera measurements and interferometric measurement techniques. For this, the laser is operated in the single-And two-color emission regime using both an etalon and a free-running configuration without etalon, respectively. The laser emission is analyzed with respect to pump power and output coupling losses for a long and for a short resonator. We observe a steep increase of emission bandwidth close to the laser threshold and monitor the transition between longitudinal single-And multi-mode operation. Additionally, the results indicate that a stable two-color operation is related to a sufficiently high number of oscillating longitudinal modes within each color. ©2013 Optical Society of America. © 2013 Optical Society of America.
• Wichmann, M., Shakfa, M. K., Zhang, F., Heinen, B., Scheller, M., Rahimi-Iman, A., Stolz, W., Moloney, J. V., Koch, S. W., & Koch, M. (2013). Evolution of multi-mode operation in vertical-external-cavity surface-emitting lasers. Optics express, 21(26), 31940--31950.
• Ament, C., Kolesik, M., Moloney, J. V., & Polynkin, P. (2012). Self-focusing dynamics of ultraintense accelerating Airy waveforms in water. Physical Review A - Atomic, Molecular, and Optical Physics, 86(4).
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  Abstract: We report experiments and numerical simulations on the self-focusing and filamentation of ultraintense femtosecond Airy waveforms in water. The accelerating property of Airy waveforms results in the generation of distinct features in the angularly resolved spectra of forward-propagating supercontinuum emission. Fitting these features with appropriate phase-matching conditions allows for the quantification of the propagation history of the waveforms. © 2012 American Physical Society.
• Ament, C., Kolesik, M., Moloney, J. V., & Polynkin, P. (2012). Self-focusing dynamics of ultraintense accelerating Airy waveforms in water. Physical Review A, 86(4), 043842.
• Ariunbold, G. O., Polynkin, P., & Moloney, J. V. (2012). Third and fifth harmonic generation by tightly focused femtosecond pulses at 2.2 $\mu$m wavelength in air. Optics express, 20(2), 1662--1667.
• Ariunbold, G. O., Polynkin, P., & Moloney, J. V. (2012). Third and fifth harmonic generation by tightly focused femtosecond pulses at 2.2μm wavelength in air. Optics Express, 20(2), 1662-1667.
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  PMID: 22274508;Abstract: We report experiments on the generation of third and fifth harmonics of millijoule-level, tightly focused, femtosecond laser pulses at 2.2μm wavelength in air. The measured ratio of yields of the third and fifth harmonics in our setup is found equal to 2 7middot; 10-4. This result contradicts the recent suggestion that the Kerr effect in air saturates and changes sign in ultra-intense optical fields. © 2012 Optical Society of America.
• Brown, J., Wright, E., Moloney, J., & Kolesik, M. (2012). On the relative roles of higher-order nonlinearity and ionization in ultrafast light-matter interactions. Optics letters, 37(10), 1604--1606.
• Chernikov, A., Wichmann, M., Shakfa, M. K., Scheller, M., Moloney, J. V., Koch, S. W., & Koch, M. (2012). Time-dynamics of the two-color emission from vertical-external-cavity surface-emitting lasers. Applied Physics Letters, 100(4).
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  Abstract: The temporal stability of a two-color vertical-external-cavity surface-emitting laser is studied using single-shot streak-camera measurements. The collected data is evaluated via quantitative statistical analysis schemes. Dynamically stable and unstable regions for the two-color operation are identified and the dependence on the pump conditions is analyzed. © 2012 American Institute of Physics.
• Chernikov, A., Wichmann, M., Shakfa, M., Scheller, M., Moloney, J., Koch, S., & Koch, M. (2012). Time-dynamics of the two-color emission from vertical-external-cavity surface-emitting lasers. Applied Physics Letters, 100(4), 041114.
• Graf, T., Christodoulides, D., Mills, M., Moloney, J., Venkataramani, S., & Wright, E. (2012). Propagation of Gaussian-apodized paraxial beams through first-order optical systems via complexcoordinate transforms and ray transfer matrices. JOSA A, 29(9), 1860--1869.
• Heinen, B., Wang, T. -., Sparenberg, M., Weber, A., Kunert, B., Hader, J., Koch, S. W., Moloney, J. V., Koch, M., & Stolz, W. (2012). 106 W continuous-wave output power from vertical-external-cavity surface-emitting laser. Electronics Letters, 48(9), 516-517.
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  Abstract: A report is presented on an optically-pumped semiconductor disk laser providing a continuous-wave output power of 106W at a heatsink temperature of 3°C. The laser, which operates in the transversal multimode regime, emits at a wavelength of 1028nm. This high output power is achieved by carefully optimising the chip design, the growth process, and the bonding layer. © 2012 The Institution of Engineering and Technology.
• Heinen, B., Wang, T., Sparenberg, M., Weber, A., Kunert, B., Hader, J., Koch, S., Moloney, J., Koch, M., & Stolz, W. (2012). 106 W continuous-wave output power from vertical-external-cavity surface-emitting laser. Electronics letters, 48(9), 516--517.
• Jakobsen, P., & Moloney, J. (2012). The effect of longitudinal electric field components on the propagation of intense ultrashort optical pulses. Physica D: Nonlinear Phenomena, 241(19), 1603--1611.
• Jakobsen, P., & Moloney, J. V. (2012). The effect of longitudinal electric field components on the propagation of intense ultrashort optical pulses. Physica D: Nonlinear Phenomena, 241(19), 1603-1611.
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  Abstract: In this paper we investigate the effect of longitudinal electric field components on the propagation of intense ultrashort optical pulses. We find that the longitudinal electric field components have contributions both from modes that in the paraxial limit are polarized transversely to the beam axis and traveling along the beam axis and from a mode that is polarized along the beam axis even in the paraxial limit and that travel transversely to the beam axis. We show that the amplitude of this last mode in general satisfies a dispersive wave equation in the plane transverse to the beam axis and that the source term in this equation depends on the amplitude of both types of modes. The source is large if the fields are intense, the pulse is short or the fields are nonparaxial. Thus the effect of the mode that is polarized along the beam axis is to transport energy away from the collapse region and in this way make the system less prone to self-focusing collapse. In the weakly nonlinear slowly varying limit we show explicitly that the effect of the longitudinally polarized mode is to restrict the range of transverse modulationally unstable wavenumbers and to act as a defocusing lens in the collapse region. © 2012 Elsevier B.V. All rights reserved.
• Kolesik, M., Jakobsen, P., & Moloney, J. (2012). Quantifying the limits of unidirectional ultrashort optical pulse propagation. Physical review A, 86(3), 035801.
• Kolesik, M., Jakobsen, P., & Moloney, J. (2012). Quantum optics, physics of lasers, nonlinear optics, classical optics-Quantifying the limits of unidirectional ultrashort optical pulse propagation (4 pages) 035801. Physical Review-Section A-Atomic Molecularand Optical Physics, 86(3).
• Kolesik, M., Jakobsen, P., & Moloney, J. V. (2012). Quantifying the limits of unidirectional ultrashort optical pulse propagation. Physical Review A - Atomic, Molecular, and Optical Physics, 86(3).
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  Abstract: In this paper we explore the limits of the unidirectional pulse propagation equation (UPPE) in general nonlinear media. Our main aim is to investigate under which physical conditions two-way propagation becomes significant, and leads to a breakdown of the unidirectional approximation. Using a spectral constraint appearing in the derivation of UPPE we derive a first correction which renormalizes the forward-propagating amplitude. This correction is the main result of our paper and we investigate its effects through numerical simulations. © 2012 American Physical Society.
• Kolesik, M., Townsend, P., & Moloney, J. V. (2012). Theory and simulation of ultrafast intense pulse propagation in extended media. IEEE Journal on Selected Topics in Quantum Electronics, 18(1), 494-506.
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  Abstract: The theory of femtosecond pulse propagation in dispersive nonlinear media is reviewed with emphasis on modeling light-matter interactions in femtosecond optical filaments. Discussion of the principles underlying the pulse propagation models is followed by the description of the standard light-medium interaction model utilized in the ultrafast nonlinear optics, and open problems are identified across the field. © 2006 IEEE.
• Kolesik, M., Whalen, P. T., & Moloney, J. V. (2012). Theory and simulation of ultrafast intense pulse propagation in extended media. IEEE Journal of Selected Topics in Quantum Electronics, 18(1), 494.
• Laurain, A., Wang, T., Yarborough, M. J., Hader, J., Moloney, J. V., Koch, S. W., Kunert, B., & Stolz, W. (2012). High Peak Power Operation of a 1-$\mu$ m GaAs-Based Optically Pumped Semiconductor Laser. Photonics Technology Letters, IEEE, 24(5), 380--382.
• Laurain, A., Wang, T., Yarborough, M. J., Hader, J., Moloney, J. V., Koch, S. W., Kunert, B., & Stolz, W. (2012). High peak power operation of a 1-μm GaAs-based optically pumped semiconductor laser. IEEE Photonics Technology Letters, 24(5), 380-382.
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  Abstract: We report room-temperature high-peak-power operation of an optically pumped semiconductor laser based on the InGaAs/GaAs material system. We present the design of the semiconductor structure and optimization strategies to extract the maximum pulsed peak power. The gain structure was pumped by a 775-nm Alexandrite laser with a pulsewidth adjustable from 400 ns to 1 μs and a repetition rate of 3 Hz. A new record peak power of 400 W at a wavelength of 1020 nm was obtained with a Gaussian-shaped submicrosecond pulse. An optical-to-optical efficiency of 28% is demonstrated at maximum power. The key parameters limiting the output power are discussed. © 2011 IEEE.
• Liu, J., Brio, M., & Moloney, J. V. (2012). Computation of Optical Force on Nanoparticles Using Locally Non-Orthogonal Overlapping Yee FDTD Method. Journal of Electromagnetic Analysis and Applications, 4, 452.
• Liu, J., Brio, M., & Moloney, J. V. (2012). Subpixel smoothing finite-difference time-domain method for material interface between dielectric and dispersive media. Optics letters, 37(22), 4802--4804.
• Mills, M., Siviloglou, G., Efremidis, N., Graf, T., Wright, E., Moloney, J., & Christodoulides, D. (2012). Localized waves with spherical harmonic symmetries. Physical Review A, 86(6), 063811.
• Pasenow, B., Moloney, J. V., Koch, S. W., Chen, S. H., Becker, A., & Jaroń-Becker, A. (2012). Nonequilibrium evolution of strong-field anisotropic ionized electrons towards a delayed plasma-state. Optics Express, 20(3), 2310-2318.
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  PMID: 22330470;Abstract: Rigorous quantum calculations of the femtosecond ionization of hydrogen atoms in air lead to highly anisotropic electron and ion angular (momentum) distributions. A quantum Monte-Carlo analysis of the subsequent many-body dynamics reveals two distinct relaxation steps, first to a nearly isotropic hot nonequilibrium and then to a quasi-equilibrium configuration. The collective isotropic plasma state is reached on a picosecond timescale well after the ultrashort ionizing pulse has passed. © 2012 Optical Society of America.
• Pasenow, B., Moloney, J., Koch, S., Chen, S., Becker, A., & Jaro\'n-Becker, A. (2012). Nonequilibrium evolution of strong-field anisotropic ionized electrons towards a delayed plasma-state. Optics express, 20(3), 2310--2318.
• Polynkin, P., Pasenhow, B., Driscoll, N., Scheller, M., Wright, E. M., & Moloney, J. V. (2012). Seeded optically driven avalanche ionization in molecular and noble gases. Physical Review A, 86(4), 043410.
• Scheller, M., Koch, S. W., & Moloney, J. V. (2012). Grating-based wavelength control of single-and two-color vertical-external-cavity-surface-emitting lasers. Optics Letters, 37(1), 25-27.
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  PMID: 22212779;Abstract: Wide wavelength tunability of single-and two-color operating vertical-external-cavity-surface-emitting lasers (VECSELs) is demonstrated. Employing an external feedback based on a diffractive grating outside the cavity of a narrow-line single-color VECSEL allows for a continuous tuning of the emission wavelength over 10 nm. Employing a dual-feedback-configuration for tunable two-color emission, a tunability of the difference frequency between the two lasing wavelengths from 300 gigahertz to up to 3.5 terahertz is demonstrated. © 2011 Optical Society of America.
• Scheller, M., Koch, S. W., & Moloney, J. V. (2012). Grating-based wavelength control of single-and two-color vertical-external-cavity-surface-emitting lasers. Optics letters, 37(1), 25--27.
• Scheller, M., Wang, T. -., Kunert, B., Stolz, W., Koch, S. W., & Moloney, J. V. (2012). Passively modelocked VECSEL emitting 682fs pulses with 5.1 W of average output power. Electronics Letters, 48(10), 588-589.
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  Abstract: A quantum-well vertical-external-cavity surface-emitting laser in combination with a quantum-well SESAM is used to generate femtosecond pulses. The passively modelocked VECSEL operates at room temperature emitting an average output power of 5.1W at 1030nm. At a repetition rate of 1.71GHz, the 682 fs pulses are nearly transform limited. © 2012 The Institution of Engineering and Technology.
• Scheller, M., Wang, T., Kunert, B., Stolz, W., Koch, S., & Moloney, J. (2012). Passively modelocked VECSEL emitting 682 fs pulses with 5.1 W of average output power. Electronics letters, 48(10), 588--589.
• Scheller, M., Young, A. G., Yarborough, J. M., Moloney, J. V., Koch, S. W., d'Aubigny, C. Y., & Walker, C. K. (2012). Heterodyne Detection of Intracavity Generated Terahertz Radiation. Terahertz Science and Technology, IEEE Transactions on, 2(3), 271--277.
• Wang, T., Heinen, B., Hader, J., Dineen, C., Sparenberg, M., Weber, A., Kunert, B., Koch, S. W., Moloney, J. V., Koch, M., & Stolz, W. (2012). Quantum design strategy pushes high-power vertical-external-cavity surface-emitting lasers beyond 100 W. Laser and Photonics Reviews, 6(5), L12-L14.
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  Abstract: Combining rigorous quantum epitaxial design, highly accurate growth, novel processing and thermal management pushes the output power of single chip vertical-external-cavity surface-emitting lasers (VECSELs) beyond the 100 W milestone. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
• Wang, T., Heinen, B., Hader, J., Dineen, C., Sparenberg, M., Weber, A., Kunert, B., Koch, S. W., Moloney, J. V., Koch, M., & others, . (2012). Quantum design strategy pushes high-power vertical-external-cavity surface-emitting lasers beyond 100 W. Laser \& Photonics Reviews, 6(5), L12--L14.
• Whalen, P., Moloney, J., Newell, A., Newell, K., & Kolesik, M. (2012). Optical shock and blow-up of ultrashort pulses in transparent media. Physical Review A, 86(3), 033806.
• Albrecht, A. R., Hains, C. P., Rotter, T. J., Stintz, A., Malloy, K. J., Balakrishnan, G., & Moloney, J. V. (2011). High power 1.25 $\mu$m InAs quantum dot vertical external-cavity surface-emitting laser. Journal of Vacuum Science \& Technology B, 29(3), 03C113.
• Albrecht, A. R., Hains, C. P., Rotter, T. J., Stintz, A., Malloy, K. J., Balakrishnan, G., & Moloney, J. V. (2011). High power 1.25 μm InAs quantum dot vertical external-cavity surface-emitting laser. Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures, 29(3).
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  Abstract: The authors demonstrate InAs quantum dot (QD)-based optically pumped vertical external-cavity surface-emitting lasers grown by molecular beam epitaxy. Active region designs utilizing two different resonant periodic gain (RPG) structures are compared. The first RPG structure is a more traditional design consisting of three QD layers per antinode of the E-field standing wave, repeated four times, for a total of 12 QD layers. The second RPG has a single-QD layer per antinode, repeated 12 times. The single-QD layer per antinode structure allows for both superior strain relief as well as more complete pump absorption and thus results in significantly improved device performance over the traditional multi-QD layer per antinode design. The authors were able to demonstrate over 3 W of output power at room temperature using a thermal grade polycrystalline chemical-vapor deposition diamond heat spreader mounted on the backside of a sample thinned by mechanical polishing. © 2011 American Vacuum Society.
• Albrecht, A. R., Rotter, T. J., Hains, C. P., Stintz, A., Xin, G., Kaneda, Y., Moloney, J. V., Malloy, K. J., Balakrishnan, G., & Wang, T. L. (2011). High-power 1.25 µm InAs QD VECSEL based on resonant periodic gain structure. Proceedings of SPIE, 7919. doi:10.1117/12.874321
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  We compare an InAs quantum dot (QD) vertical external-cavity surface-emitting laser (VECSEL) design consisting of 4 groups of 3 closely spaced QD layers with a resonant periodic gain (RPG) structure, where each of the 12 QD layers is placed at a separate field antinode. This increased the spacing between the QDs, reducing strain and greatly improving device performance. For thermal management, the GaAs substrate was thinned and indium bonded to CVD diamond. A fiber-coupled 808 nm diode laser was used as pump source, a 1% transmission output coupler completed the cavity. CW output powers over 4.5 W at 1250 nm were achieved.
• Ament, C., Polynkin, P., & Moloney, J. V. (2011). Supercontinuum generation with femtosecond self-healing airy pulses. Physical Review Letters, 107(24).
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  PMID: 22243000;Abstract: We report experiments and numerical simulations on supercontinuum generation with femtosecond Airy pulses in a highly nonlinear optical fiber. The ability of the Airy waveform to regenerate its dominant intensity peak results in the generation of distinct spectral features. Airy pulses and other self-healing temporal waveforms may be useful for the generation of spectra with desired properties. © 2011 American Physical Society.
• Ament, C., Polynkin, P., & Moloney, J. V. (2011). Supercontinuum generation with femtosecond self-healing airy pulses. Physical review letters, 107(24), 243901.
• B\"aumner, A., Koch, S. W., & Moloney, J. V. (2011). Non-equilibrium analysis of the two-color operation in semiconductor quantum-well lasers. physica status solidi (b), 248(4), 843--846.
• B\"uckers, C., Hader, J., Moloney, J. V., & Koch, S. W. (2011). Microscopic simulation of semiconductor laser devices. physica status solidi (c), 8(9), 2558--2563.
• Balakrishnan, G., Rotter, T. J., Ahirwar, P., Clark, S. P., Patel, V., Hains, C. P., Lai, Y. Y., Wang, T. L., Yarborough, J. M., Kaneda, Y., Moloney, J. V., Moloney, J. V., Hader, J., Koch, S. W., Mathine, D. L., & Albrecht, A. R. (2011). Lattice mismatched growth for mid-IR VECSELs. Proceedings of SPIE, 7919. doi:10.1117/12.874234
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  We demonstrate a novel epitaxial process for the growth of low-dislocation density GaSb on GaAs. The growth mode involves the formation of large arrays of periodic 90° misfit dislocations at the interface between the two binary alloys which results in a completely strain relieved III-Sb epi-layer without the need for thick buffer layers. This epitaxial process is used for the growth of antimonide active regions directly on GaAs/AlGaAs distributed Bragg Reflectors (DBRs) resulting in 2 μm VECSELs on GaAs substrates.
• Bedford, R. G., Triplett, G., Tomich, D. H., Koch, S. W., Moloney, J., & Hader, J. (2011). Reduced auger recombination in mid-infrared semiconductor lasers. Journal of Applied Physics, 110(7), 073108.
• Bedford, R. G., Triplett, G., Tomich, D. H., Koch, S. W., Moloney, J., & Hader, J. (2011). Reduced auger recombination in mid-infrared semiconductor lasers. Journal of Applied Physics, 110(7).
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  Abstract: A quantum-design approach to reduce the Auger losses in λ = 2 μm InGaSb type-I quantum well edge-emitting lasers is reported. Experimentally realized structures show a ∼3 × reduction in the threshold, which results in 4.6 × lower Auger current loss at room temperature. This is equivalent to a carrier lifetime improvement of 5.7 × and represents about a 19-fold reduction in the equivalent Auger coefficient. © 2011 American Institute of Physics.
• Bäumner, A., Koch, S. W., & Moloney, J. V. (2011). Non-equilibrium analysis of the two-color operation in semiconductor quantum-well lasers. Physica Status Solidi (B) Basic Research, 248(4), 843-846.
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  Abstract: The relevance of hole burning for stable two-color operation in semiconductor quantum-well lasers is studied using a non-equilibrium laser model on the basis of the semiconductor Maxwell-Bloch equations. The field propagation is described via a traveling-wave method. The polarization dynamics is computed using the semiconductor Bloch equations for the microscopic transition and occupation probabilities. Numerical examples for single- and dual-mode operation are presented for a microresonator model system. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
• Bückers, C., Hader, J., Moloney, J. V., & Koch, S. W. (2011). Microscopic simulation of semiconductor laser devices. Physica Status Solidi (C) Current Topics in Solid State Physics, 8(9), 2558-2563.
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  Abstract: This paper reviews the application of a systematic microscopic theory for the optical and electronic properties of semiconductors. The theory is applied to quantitatively model and analyze different semiconductor systems. Detailed theory-experiment comparisons are shown for a variety of quantum well gain materials. It is demonstrated how the analysis can be used to aid in the design of modern semiconductor laser devices. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
• Chernikov, A., Herrmann, J., Koch, M., Kunert, B., Stolz, W., Chatterjee, S., Koch, S. W., Wang, T., Kaneda, Y., Yarborough, J. M., & others, . (2011). Heat management in high-power vertical-external-cavity surface-emitting lasers. Selected Topics in Quantum Electronics, IEEE Journal of, 17(6), 1772--1778.
• Chernikov, A., Herrmann, J., Koch, M., Kunert, B., Stolz, W., Chatterjee, S., Koch, S. W., Wang, T., Kaneda, Y., Yarborough, J. M., Hader, J., & Moloney, J. V. (2011). Heat management in high-power vertical-external-cavity surface-emitting lasers. IEEE Journal on Selected Topics in Quantum Electronics, 17(6), 1772-1778.
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  Abstract: The thermal properties of a high-power vertical-external-cavity surface-emitting laser (VECSEL) are studied experimentally, focusing on the generation, distribution, and removal of excess heat under extreme pumping conditions. Different heat-spreading and heat-transfer approaches are analyzed. The performance of the device is optimized yielding a maximum emitted power beyond 70W from a single spot. Finally, the potential for power-scaling in VECSELs and its restrictions are examined. © 2006 IEEE.
• Clark, S. P., Ahirwar, P., Jaeckel, F. T., Hains, C. P., Albrecht, A. R., Rotter, T. J., Dawson, L. R., Balakrishnan, G., Hopkins, P. E., Phinney, L. M., Hader, J., & Moloney, J. V. (2011). Growth and thermal conductivity analysis of polycrystalline GaAs on chemical vapor deposition diamond for use in thermal management of high-power semiconductor lasers. Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures, 29(3).
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  Abstract: The authors demonstrate the growth of polycrystalline GaAs thin films on polycrystalline chemical vapor deposition (CVD) diamond by low-temperature molecular beam epitaxy. The low-temperature GaAs (LT-GaAs) layer is easily polished compared to the CVD diamond, and this process results in a reduction of rms surface roughness from 50 to
• Clark, S., Ahirwar, P., Jaeckel, F., Hains, C., Albrecht, A., Rotter, T., Dawson, L., Balakrishnan, G., Hopkins, P., Phinney, L., & others, . (2011). Growth and thermal conductivity analysis of polycrystalline GaAs on chemical vapor deposition diamond for use in thermal management of high-power semiconductor lasers. Journal of Vacuum Science \& Technology B, 29(3), 03C130.
• Glasner, K., Kolesik, M., Moloney, J. V., & Newell, A. C. (2011). Canonical and singular propagation of ultrashort pulses in a nonlinear medium. International journal of optics, 2012.
• Hader, J., Moloney, J. V., & Koch, S. W. (2011). Density-activated defect recombination as a possible explanation for the efficiency droop in GaN-based diodes. Proceedings of SPIE, 7954. doi:10.1117/12.873941
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  A model based on density-activated defect recombination processes is proposed as a possible explanation for the efficiency droop in GaN-based lasers. The model yields very good agreement with experimentally measured efficiencies based on fit parameters that indicate the presence of two types of recombination centers that have different local distributions and recombination rates. The recombination rates of the two types are found to be very similar for devices operating at 530nm and 410nm.
• Hader, J., Moloney, J. V., & Koch, S. W. (2011). Temperature-dependence of the internal efficiency droop in GaN-based diodes. Applied Physics Letters, 99(18).
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  Abstract: The temperature dependence of the measured internal efficiencies of green and blue emitting InGaN-based diodes is analyzed. With increasing temperature, a strongly decreasing strength of the loss mechanism responsible for droop is found which is in contrast to the usually assumed behavior of Auger losses. However, the experimental observations can be well reproduced assuming density activated defect recombination with a temperature independent recombination time. © 2011 American Institute of Physics.
• Hader, J., Moloney, J., & Koch, S. (2011). Temperature-dependence of the internal efficiency droop in GaN-based diodes. Applied Physics Letters, 99(18), 181127.
• Hader, J., Wang, T., Yarborough, J. M., Dineen, C. A., Kaneda, Y., Moloney, J. V., Kunert, B., Stolz, W., & Koch, S. W. (2011). VECSEL optimization using microscopic many-body physics. IEEE Journal on Selected Topics in Quantum Electronics, 17(6), 1753-1762.
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  Abstract: Vertical external cavity surface-emitting lasers (VECSELs) are designed and analyzed using an approach based on fully microscopically computed material properties like gain and carrier recombination rates. Very good agreement between theoretical predictions and measured characteristics of the realized devices is demonstrated. The high accuracy of the theoretical models allows one to determine even small deviations between the nominal designs and actual realizations. The models are used to find optimization strategies. It is shown how the external efficiency can be strongly improved using surface coatings that reduce the pump reflection while retaining the gain-enhancing cavity effects at the lasing wavelength. It is shown how incomplete pump absorption can be detrimental to the device performance and how this problem can be reduced using optimized distributed Bragg reflectors and metallization layers. A combination of improved metallization and use of such a coating more than doubles the external efficiency and maximum power for a realized VECSEL operating at 1010 nm and the theory indicates that further significant improvements are possible. © 2006 IEEE.
• Hader, J., Wang, T., Yarborough, J. M., Dineen, C. A., Kaneda, Y., Moloney, J. V., Kunert, B., Stolz, W., & Koch, S. W. (2011). VECSEL optimization using microscopic many-body physics. Selected Topics in Quantum Electronics, IEEE Journal of, 17(6), 1753--1762.
• Hessenius, C., Fallahi, M., Moloney, J. V., Terry, N. B., Hessenius, C., Fallahi, M., & Bedford, R. G. (2011). Gain coupling VECSELs. Proceedings of SPIE, 7919. doi:10.1117/12.873864
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  Vertical external cavity surface emitting lasers (VECSELs) provide a laser design platform in order to explore a variety of systems, and their flexibility eases this exploration. Moreover, their high-brightness operation makes them attractive for many applications. In considering the methods of coupling VECSELs as well as their potential uses, we begin by reporting on the development of a gain coupled VECSEL for use in optical switching. In particular, two VECSEL cavities share a common gain region; the competition for a common set of carriers dictate how these cavities interact. The easiest manifestation to realize gain coupling is to utilize a linear cavity as well as a v-cavity, built around a single half-vertical cavity surface-emitting laser (VCSEL) chip. The cavity gain/loss of each cavity can be controlled independently through use of birefringent filters, allowing us to explore the design space, which can be divided up into coarse behavior, easy to analyze through comparing the two uncoupled lasers, and a fine behavior, where one cavity will affect the other and each cavity can lase simultaneously, sometimes at dramatically different wavelengths. These two regions may be explained with simple rate equations, and it will be shown that if prepared properly, spontaneous emission plays a large role in balancing the two laser cavities within the fine regime, while may be completely neglected in the coarse regime.
• Hessenius, C., Fallahi, M., Moloney, J. V., Terry, N. B., Hessenius, C., Fallahi, M., & Bedford, R. G. (2011). Latest Progress in High Power VECSELs. Proceedings of SPIE, 7945. doi:10.1117/12.873871
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  Vertical external cavity surface emitting lasers (VECSELs) have captured the interest of high-brightness semiconductor researchers, primarily due to their simplicity in design, power scalability, and "open cavity architecture," wherein it is simple to integrate nonlinear elements into the cavity. Through direct emission and indirect (frequency-converted) means, wavelengths from the UV through to the mid-wave infrared regimes have been demonstrated, increasing the suitability of the VECSEL platform for multiple applications. This presentation outlines recent progress in VECSELs, measurements, novel cavities, and potential applications for these lasers.
• Hessenius, C., Moloney, J. V., Hessenius, C., Fallahi, M., & Bedford, R. (2011). Lateral lasing and ASE reduction in VECSELs. Proceedings of SPIE, 7919. doi:10.1117/12.875595
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  Vertical external cavity surface emitting lasers (VECSELs) are attractive for many applications due to their high-power, high-brightness outputs. In order to power scale the devices, the pump spot size should be increased. However, the large pump area greatly amplifies the guided spontaneous emission in the epitaxial plane. In order to efficiently power scale the devices, amplified spontaneous emission (ASE) and lateral lasing must be reduced. We begin by first reporting on the temperature dependence of the phenomena. Particularly, since the quantum well gain and bandgap are functions of temperature, ASE and lateral lasing are greatly dependent on the operating temperature as well as the pump power. The easiest method of quantifying the affect of ASE and lateral lasing is by removing the Fabry-Perot cavity formed by the chip edges. We have chosen two different methods: Reducing the Fresnel reflections by patterning the edges of the sample, and depositing a layer of Ge on the edges of the VECSEL chip as the high index of refraction for Ge should reduce the Fresnel reflections and the absorption properties in the NIR regime should also act to prevent feedback into the pump area. Our research shows both of these methods have increased the performance and visibly decreased the amount of lateral lasing seen in the devices.
• Lermer, T., Gomez-Iglesias, A., Sabathil, M., M\"uller, J., Lutgen, S., Strauss, U., Pasenow, B., Hader, J., Moloney, J., Koch, S., & others, . (2011). Gain of blue and cyan InGaN laser diodes. Applied Physics Letters, 98(2), 021115.
• Lermer, T., Gomez-Iglesias, A., Sabathil, M., Müller, J., Lutgen, S., Strauss, U., Pasenow, B., Hader, J., Moloney, J. V., Koch, S. W., Scheibenzuber, W., & Schwarz, U. T. (2011). Gain of blue and cyan InGaN laser diodes. Applied Physics Letters, 98(2).
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  Abstract: Experimental gain spectra of 450 and 490 nm laser diodes on c-plane GaN are analyzed by detailed comparison with the results of a fully microscopic theory. The gain calculation shows the importance of electron LO-phonon coupling. The whole spectral gain shape, not only the low energy tail, is strongly influenced by the LO-phonon contribution. The inhomogeneous broadening parameter increases by a factor of about two for the cyan laser diode in comparison with the blue laser structure. This indicates an increase in alloy and thickness fluctuations for the longer wavelength material. © 2011 American Institute of Physics.
• Moloney, J. V., Hader, J., Bückers, C., & Koch, S. W. (2011). Microscopic simulation of semiconductor laser devices. physica status solidi c, 8(9), 2558-2563. doi:10.1002/pssc.201084137
• Moloney, J. V., Scheller, M., Yarborough, J. M., Koch, S. W., Koch, M., & Fallahi, M. (2011). Compact, high-power, room-temperature, narrow-line terahertz source. SPIE Newsroom, DOI.
• Paul, J., Kaneda, Y., Wang, T., Lytle, C., Moloney, J. V., & Jones, R. J. (2011). Doppler-free spectroscopy of mercury at 253.7 nm using a high-power, frequency-quadrupled, optically pumped external-cavity semiconductor laser. Optics Letters, 36(1), 61-63.
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  PMID: 21209687;Abstract: We have developed a stable, high-power, single-frequency optically pumped external-cavity semiconductor laser system and generate up to 125 mW of power at 253:7 nm using successive frequency doubling stages. We demonstrate precision scanning and control of the laser frequency in the UV to be used for cooling and trapping of mercury atoms. With active frequency stabilization, a linewidth of 1 W) optically pumped semiconductor laser system. The results demonstrate the utility of these devices for precision spectroscopy at deep-UV wavelengths. © 2010 Optical Society of America.
• Paul, J., Kaneda, Y., Wang, T., Lytle, C., Moloney, J. V., & Jones, R. J. (2011). Doppler-free spectroscopy of mercury at 253.7 nm using a high-power, frequency-quadrupled, optically pumped external-cavity semiconductor laser. Optics letters, 36(1), 61--63.
• Polynkin, P., & Moloney, J. V. (2011). Optical breakdown of air triggered by femtosecond laser filaments. Applied Physics Letters, 99(15), 151103.
• Polynkin, P., & Moloney, J. V. (2011). Optical breakdown of air triggered by femtosecond laser filaments. Applied Physics Letters, 99(15).
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  Abstract: We report experiments on the generation of dense plasma channels in ambient air using a dual laser pulse excitation scheme. The dilute plasma produced through the filamentation of an ultraintense femtosecond laser pulse is densified via avalanche ionization driven by a co-propagating multi-Joule nanosecond pulse. © 2011 American Institute of Physics.
• Polynkin, P., Kolesik, M., Wright, E. M., & Moloney, J. V. (2011). Experimental tests of the new paradigm for laser filamentation in gases. Physical review letters, 106(15), 153902.
• Shiffler, S., Polynkin, P., & Moloney, J. (2011). Self-focusing of femtosecond diffraction-resistant vortex beams in water. Optics Letters, 36(19), 3834-3836.
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  PMID: 21964113;Abstract: We report experiments on self-focusing of femtosecond diffraction-resistant vortex beams in water. These beams are higher-order Bessel beams with weak azimuthal modulation of the transverse intensity patterns. The modulation overrides the self-focusing dynamics and results in the formation of regular bottlelike filament distributions. The peak-power thresholds for filamentation, at a particular distance, are relatively accurately estimated by the adaptation of the Marburger formula derived earlier for Gaussian beams. The nonlinear conversion of the incident conical waves into the localized spatial wave packets propagating near the beam axis is observed. © 2011 Optical Society of America.
• Shiffler, S., Polynkin, P., & Moloney, J. (2011). Self-focusing of femtosecond diffraction-resistant vortex beams in water. Optics letters, 36(19), 3834--3836.
• Whalen, P., Moloney, J. V., & Kolesik, M. (2011). Self-focusing collapse distance in ultrashort pulses and measurement of nonlinear index. Optics Letters, 36(13), 2542-2544.
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  PMID: 21725473;Abstract: We analyze the method of moving focus to determine the critical power for self-focusing by means of numerical simulation and a semianalytical model. It is shown that the original interpretation of a moving focus experiment does not hold in general and that inclusion of defocusing effects due to free electrons is necessary to relate the measured data to critical power. © 2011 Optical Society of America.
• Whalen, P., Moloney, J., & Kolesik, M. (2011). Self-focusing collapse distance in ultrashort pulses and measurement of nonlinear index. Optics letters, 36(13), 2542--2544.
• Albrecht, A. R., Rotter, T. J., Hains, C. P., Stintz, A., Moloney, J. V., Malloy, K. J., & Balakrishnan, G. (2010). Multi-watt 1.25m quantum dot VECSEL. Electronics Letters, 46(12), 856-857.
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  Abstract: An InAs quantum dot (QD) vertical external cavity surface-emitting laser (VECSEL) operating at a wavelength of 1.25m is reported. The gain region of the laser consists of a resonant periodic gain structure using single QD layers at 12 adjacent electrical field antinodes - a design optimised to reduce strain accumulation and improve QD quality. A fibre-coupled 808nm laser diode is used as a pump source and a spherical external mirror completes the cavity. Thermal management is accomplished by bonding the VECSEL sample to a chemical vapour deposition (CVD) diamond heat spreader. Continuous wave output powers in excess of 3 W have been achieved at room temperature. The broad emission spectrum makes this device an ideal candidate for wavelength tunable or modelocked applications. © 2010 The Institution of Engineering and Technology.
• Albrecht, A., Rotter, T., Hains, C., Stintz, A., Moloney, J., Malloy, K., & Balakrishnan, G. (2010). Multi-watt 1.25 $\mu$m quantum dot VECSEL. Electronics letters, 46(12), 856--857.
• B\"uckers, C., K\"uhn, E., Schlichenmaier, C., Imhof, S., Thr\"anhardt, A., Hader, J., Moloney, J. V., Rubel, O., Zhang, W., Ackemann, T., & others, . (2010). Quantum modeling of semiconductor gain materials and vertical-external-cavity surface-emitting laser systems. physica status solidi (b), 247(4), 789--808.
• Bückers, C., Kühn, E., Schlichenmaier, C., Imhof, S., Thränhardt, A., Hader, J., Moloney, J. V., Rubel, O., Zhang, W., Ackemann, T., & Koch, S. W. (2010). Quantum modeling of semiconductor gain materials and vertical-external- cavity surface-emitting laser systems. Physica Status Solidi (B) Basic Research, 247(4), 789-808.
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  Abstract: This article gives an overview of the microscopic theory used to quantitatively model a wide range of semiconductor laser gain materials. As a snapshot of the current state of research, applications to a variety of actual quantum-well systems are presented. Detailed theory-experiment comparisons are shown and it is analyzed how the theory can be used to extract poorly known material parameters. The intrinsic laser loss processes due to radiative and nonradiative Auger recombination are evaluated microscopically. The results are used for realistic simulations of vertical-external-cavity surface-emitting laser systems. To account for nonequilibrium effects, a simplified model is presented using pre-computed microscopic scattering and dephasing rates. Prominent deviations from quasi-equili- brium carrier distributions are obtained under strong in-well pumping conditions. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
• Chernikov, A., Herrmann, J., Scheller, M., Koch, M., Kunert, B., Stolz, W., Chatterjee, S., Koch, S. W., Wang, T. L., Kaneda, Y., Yarborough, J. M., Hader, J., & Moloney, J. V. (2010). Influence of the spatial pump distribution on the performance of high power vertical-external-cavity surface-emitting lasers. Applied Physics Letters, 97(19).
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  Abstract: The performance of a 1040 nm vertical-external-cavity surface-emitting laser is studied as function of the size and shape of the pumped area. The input-output characteristics of the device are monitored while simultaneously tracking the temperature in the active region. It is shown that the pump spot shape plays a crucial role in optimizing the laser output. Improvements up to a factor of 5 are found for a super-Gaussian in comparison to the standard Gaussian shape. For the large pump-spot sizes needed for high output powers, it turns out that the power-scalability breaks down due to the suppressed lateral heat flow. © 2010 American Institute of Physics.
• Chernikov, A., Herrmann, J., Scheller, M., Koch, M., Kunert, B., Stolz, W., Chatterjee, S., Koch, S., Wang, T., Kaneda, Y., & others, . (2010). Influence of the spatial pump distribution on the performance of high power vertical-external-cavity surface-emitting lasers. Applied Physics Letters, 97(19), 191110.
• Faccio, D., Cacciatori, S., Gorini, V., Sala, V. G., Averchi, A., Lotti, A., Kolesik, M., & Moloney, J. V. (2010). Analogue gravity and ultrashort laser pulse filamentation. EPL, 89(3).
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  Abstract: Ultrashort laser pulse filaments in dispersive nonlinear Kerr media induce a moving refractive index perturbation which modifies the spacetime geometry as seen by co-propagating light rays. We study the analogue geometry induced by the filament and show that one of the most evident features of filamentation, namely conical emission, may be precisely reconstructed from the geodesics. We highlight the existence of favorable conditions for the study of analogue black hole kinematics and Hawking-type radiation. © 2010 Europhysics Letters Association.
• Hader, J., Hardesty, G., Wang, T., Yarborough, M. J., Kaneda, Y., Moloney, J. V., Kunert, B., Stolz, W., & Koch, S. W. (2010). Predictive microscopic modeling of VECSELs. IEEE Journal of Quantum Electronics, 46(5), 810-817.
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  Abstract: Based on fully microscopically computed material gain and carrier recombination rates, we compute the output characteristics of optically pumped Vertical External Cavity Surface Emitting Lasers. Very good agreement with experimental results is obtained where, besides broadenings introduced to model sample imperfections, the only experimental fit parameter is a correction to the pump spot diameter to account for the nonideal profile of the used pump. © 2006 IEEE.
• Hader, J., Hardesty, G., Wang, T., Yarborough, M. J., Kaneda, Y., Moloney, J. V., Kunert, B., Stolz, W., & Koch, S. W. (2010). Predictive microscopic modeling of VECSELs. IEEE journal of quantum electronics, 46(5-6), 810--817.
• Hader, J., Moloney, J. V., & Koch, S. W. (2010). Density-activated defect recombination as a possible explanation for the efficiency droop in GaN-based diodes. Applied Physics Letters, 96(22).
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  Abstract: It is shown that a carrier loss process modeling density-activated defect recombination can reproduce the experimentally observed droop of the internal quantum efficiency in GaN-based laser diodes. © 2010 American Institute of Physics.
• Hessenius, C., Terry, N., Fallahi, M., Moloney, J., & Bedford, R. (2010). Gain coupling of class A semiconductor lasers. Optics Letters, 35(18), 3060-3062.
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  PMID: 20847778;Abstract: We report on the development of a gain-coupled class A semiconductor laser for dual-wavelength generation via optical switching. A vertical external cavity surface emitting laser (VECSEL) structure is used, because it provides a flexible platform for high-power, high-brightness output in the near-IR and visible ranges. For the first time (to our knowledge), two VECSEL cavities sharing a common gain region are studied. Because the cavities are in competition for common carriers, biréfringent filters in the external cavity control the laser cavity thresholds; this configuration demonstrates the possibility of switching between the two cavities, which can operate at different wavelengths. However, in this Letter we also show, numerically and experimentally, that with the consideration of spontaneous emission, it is possible to maintain simultaneous lasing in each cavity at a different wavelength. © 2010 Optical Society of America.
• Hessenius, C., Terry, N., Fallahi, M., Moloney, J., & Bedford, R. (2010). Gain coupling of class A semiconductor lasers. Optics letters, 35(18), 3060--3062.
• K\"uhn, E., Koch, S. W., Thr\"anhardt, A., Hader, J., & Moloney, J. V. (2010). Microscopic simulation of nonequilibrium features in quantum-well pumped semiconductor disk lasers. Applied Physics Letters, 96(5), 051116.
• Kolesik, M., Mirell, D., Diels, J. -., & Moloney, J. V. (2010). On the higher-order Kerr effect in femtosecond filaments. Optics Letters, 35(21), 3685-3687.
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  PMID: 21042391;Abstract: A recent experiment probing the electronic nonlinearity in the femtosecond filament indicated that the optical Kerr effect not only saturates but even changes its sign at high intensities and thus switches from self-focusing to a strongly defocusing regime. Here we examine, through simulations and experiment, some implications of such a behavior. We perform comparative simulations based on the standard model on one hand and on a model implementing the intensity-dependent Kerr effect on the other. Comparison with an experiment provides a strong indication that of these two Kerr-effect models the standard model is better in capturing the observed length of the filament. However, neither of the models can reproduce length and filament radius. Possible implications are discussed. © 2010 Optical Society of America.
• Kolesik, M., Mirell, D., Diels, J., & Moloney, J. (2010). On the higher-order Kerr effect in femtosecond filaments. Optics letters, 35(21), 3685--3687.
• Kolesik, M., Tartara, L., & Moloney, J. (2010). Effective three-wave-mixing picture and first Born approximation for femtosecond supercontinua from microstructured fibers. Physical Review A, 82(4), 045802.
• Kolesik, M., Tartara, L., & Moloney, J. V. (2010). Effective three-wave-mixing picture and first Born approximation for femtosecond supercontinua from microstructured fibers. Physical Review A - Atomic, Molecular, and Optical Physics, 82(4).
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  Abstract: The theory of supercontinuum generation in microstructured fibers is based on notions of soliton fission and subsequent dispersive wave radiation. In bulk media, in contrast, the paradigm of effective three-wave mixing (ETWM) proves useful for understanding the supercontinuum spectral properties and revealing the dynamics within the high-intensity core of the collapsing filament. Previously, it has been shown that the bulk theory applies accurately even to so-called glass-membrane fibers in which the guided light is free to diffract in one dimension. In the same spirit, this work extends that result and brings the fiber and bulk supercontinuum approaches closer together. Specifically, we demonstrate that the ETWM paradigm can be modified for fibers, where it provides an accurate analytic description of the supercontinuum component due to dispersive waves. © 2010 The American Physical Society.
• Kolesik, M., Wright, E., & Moloney, J. (2010). Femtosecond filamentation in air and higher-order nonlinearities. Optics letters, 35(15), 2550--2552.
• Kühn, E., Koch, S. W., Thränhardt, A., Hader, J., & Moloney, J. V. (2010). Microscopic simulation of nonequilibrium features in quantum-well pumped semiconductor disk lasers. Applied Physics Letters, 96(5).
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  Abstract: A microscopically motivated nonequilibrium theory is applied to study the power characteristics of an in-well pumped vertical external cavity surface emitting Laser for varying pump energies. Dynamic simulations yield steady state nonequilibrium carrier distributions resulting in gain reduction due to kinetic hole burning. Pauli blocking effects become prominent for more resonant pumping and increased pump powers. The reduced pump absorption results in a sublinear input-output power characteristics even for the optimized case where heating of the active mirror plays no role. © 2010 American Institute of Physics.
• Lai, Y., Yarborough, J. M., Kaneda, Y., Hader, J., Moloney, J. V., Rotter, T. J., Balakrishnan, G., Hains, C., & Koch, S. W. (2010). 340-W peak power from a GaSb 2-μm optically pumped semiconductor laser (OPSL) grown mismatched on GaAs. IEEE Photonics Technology Letters, 22(16), 1253-1255.
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  Abstract: A GaSb-based vertical external cavity laser at 2 μm was pumped by 100- to 160-ns pulses from a Nd:YAG laser at 1.064 μm operating at 1 kHz. It was shown that the output power scales with the pump spot diameter to the extent of our experiments. A peak output of over 340 W was obtained. © 2006 IEEE.
• Lai, Y., Yarborough, J., Kaneda, Y., Hader, J., Moloney, J. V., Rotter, T., Balakrishnan, G., Hains, C., & Koch, S. (2010). 340-W Peak Power From a GaSb 2-m Optically Pumped Semiconductor Laser (OPSL) Grown Mismatched on GaAs. Photonics Technology Letters, IEEE, 22(16), 1253--1255.
• Liu, J., Brio, M., Zeng, Y., Zakharian, A. R., Hoyer, W., Koch, S. W., & Moloney, J. V. (2010). Generalization of the FDTD algorithm for simulations of hydrodynamic nonlinear Drude model. Journal of Computational Physics, 229(17), 5921--5932.
• Polynkin, P., Kolesik, M., Moloney, J., Siviloglou, G., & Christodoulides, D. (2010). Extreme nonlinear optics with ultra-intense self-bending Airy beams. Optics and Photonics News, 21(9), 38--43.
• Scheller, M., Yarborough, J. M., Moloney, J. V., Fallahi, M., Koch, M., & Koch, S. W. (2010). Room temperature continuous wave milliwatt terahertz source. Optics Express, 18(26), 27112-27117.
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  PMID: 21196987;Abstract: We present a continuous wave terahertz source based on intracavity difference frequency generation within a dual color vertical external cavity surface emitting laser. Using a nonlinear crystal with a surface emitting phase matching scheme allows for high conversion efficiencies. Due to the tunability of the dual mode spacing, the entire spectral range of the terahertz gap can be covered. The terahertz output scales quadratically with the intracavity intensity, potentially allowing for terahertz intensities in the range of 10s of milliwatts and beyond. © 2010 Optical Society of America.
• Scheller, M., Yarborough, J. M., Moloney, J. V., Fallahi, M., Koch, M., & Koch, S. W. (2010). Room temperature continuous wave milliwatt terahertz source. Optics express, 18(26), 27112--27117.
• Wang, T., Kaneda, Y., Yarborough, J. M., Hader, J., Moloney, J. V., Chernikov, A., Chatterjee, S., Koch, S. W., Kunert, B., & Stolz, W. (2010). High-power optically pumped semiconductor laser at 1040 nm. IEEE Photonics Technology Letters, 22(9), 661-663.
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  Abstract: We demonstrate near-diffraction limited (M2 ≈ 1.5) output up to 23.8 W with optical-to-optical efficiency 27% and slope efficiency 32.4% and 40.7 W of multimode output from an optically pumped semiconductor laser at 1040 nm. Temperature-dependent photoluminescence measurements confirm accurate epitaxial growth according to the design thereby enhancing the effective gain. © 2006 IEEE.
• Zeng, Y., Dineen, C., & Moloney, J. V. (2010). Magnetic dipole moments in single and coupled split-ring resonators. Physical Review B - Condensed Matter and Materials Physics, 81(7).
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  Abstract: We examine the role of magnetic dipoles in single and coupled pairs of metallic split-ring resonators by numerically computing their magnitude and examining their relative contributions to the scattering cross section. We demonstrate that magnetic dipoles can strongly influence the scattering cross section along particular directions. It is also found that the magnetic dipole parallel to the incident magnetic field may play a significant role in the linear response of coupled split-ring resonators. © 2010 The American Physical Society.
• Zeng, Y., Dineen, C., & Moloney, J. V. (2010). Magnetic dipole moments in single and coupled split-ring resonators. Physical Review B, 81(7), 075116.
• Zhu, X., Sch\"ulzgen, A., Li, H., Wei, H., Moloney, J., & Peyghambarian, N. (2010). Coherent beam transformations using multimode waveguides. Optics express, 18(7), 7506--7520.
• Zhu, X., Schülzgen, A., Li, H., Wei, H., Moloney, J. V., & Peyghambarian, N. (2010). Coherent beam transformations using multimode waveguides. Optics Express, 18(7), 7506-7520.
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  PMID: 20389773;Abstract: Physical insights and characteristics of beam transformations based on multimode interference (MMI) in multimode waveguides are illuminated and analyzed. Our calculations show that, utilizing a short piece of cylindrical multimode waveguide, an input Gaussian beam can be readily transformed to frequently desired beams including top-hat, donut-shaped, taper-shaped, and Bessel-like beams in the Fresnel or the Fraunhofer diffraction range, or even in both ranges. This is a consequence of diffraetive propagation of the field exiting the waveguide. The performance of the beam shaper based on MMI can be controlled via tailoring the dimensions of the multimode waveguide or changing the signal wavelength. This beam shaping technique is investigated experimentally using monolithic fiber devices consisting of a short piece of multimode fiber (∼ 10 mm long) and a single-mode signal delivery fiber. © 2010 Optical Society of America.
• AbdelMalek, F., Hongbo, L. i., Schülzgen, A., Moloney, J. V., Peyghambarian, N., Ademgil, H., & Haxha, S. (2009). A nonlinear switch based on irregular structures and nonuniformity in doped photonic crystal fibers. IEEE Journal of Quantum Electronics, 45(6), 684-693.
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  Abstract: We propose a novel nonlinear switchbased on the irregularity in a three-core-doped photonic crystal fiber (PCF). We numerically investigate the proposed structure, which consists of air holes arranged in a triangular lattice around two defects separated by a single Er-Yb doped core. Its switching operation is based on the gain change in the doped core due to the nonuniformity and irregular structure around it. It is shown that by adjusting the gain in the doped core, the light is entirely transferred from the central core to the upper and lower ones. We have employed the full vectorial finite-element method and the finite-difference time domain to investigate and optimize the optical modes, nonlinear parameter, and gain effects on the switching operation. It is found that an optimum gain is essential to allow either a periodic exchange of the light between the upper and lower cores or independent core propagation. Possible nonuniformity in the hole diameters and irregularity problems of the proposed PCF design during the fabrication process have been predicted. The waveguide dispersion with respect to the doped central core region has been thoroughly investigated. © 2009 IEEE.
• AbdelMalek, F., Li, H., Schulzgen, A., Moloney, J. V., Peyghambarian, N., Ademgil, H., & Haxha, S. (2009). A Nonlinear Switch Based on Irregular Structures and Nonuniformity in Doped Photonic Crystal Fibers. Quantum Electronics, IEEE Journal of, 45(6), 684--693.
• Brio, M., & Moloney, J. V. (2009). A DIAGONAL SPLIT-CELL MODEL FOR THE OVERLAPPING YEE FDTD METHOD. Acta Mathematica Scientia, 6, 011.
• Buckers, C., Imhof, S., Thranhardt, A., Hader, J., Moloney, J. V., & Koch, S. W. (2009). Microscopic modeling of quantum well gain media for VECSEL applications. Selected Topics in Quantum Electronics, IEEE Journal of, 15(3), 984--992.
• Bueckers, C., Kuehn, E., Schlichenmaier, C., Imhof, S., Thraenhardt, A., Hader, J., Moloney, J. V., Rubel, O., & Zhang, W. (2009). Strathprints Institutional Repository. physica status solidi.
• Bückers, C., Imhof, S., Thränhardt, A., Hader, J., Moloney, J. V., & Koch, S. W. (2009). Microscopic modeling of quantum well gain media for VECSEL applications. IEEE Journal on Selected Topics in Quantum Electronics, 15(3), 984-992.
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  Abstract: This paper summarizes a consistent microscopic approach that allows for predictive calculations of laser gain/absorption, photoluminescence, and the intrinsic laser loss processes. The theory is first evaluated for an (AlGaIn)As quantum well system used in a vertical-external-cavity surface-emitting laser structure. Good agreement with experimental results is demonstrated. In a second application, the microscopic approach is used to predict the optical properties of novel dilute bismide containing GaAs-based quantum well gain media. Modeling the bismuth-induced band structure modifications by a valence band anticrossing model, the material gain, radiative, and Auger losses are computed. © 2006 IEEE.
• Chen, S., Zang, W., Sch\"ulzgen, A., Liu, X., Tian, J., Moloney, J. V., & Peyghambarian, N. (2009). Modeling of Z-scan characteristics for one-dimensional nonlinear photonic bandgap materials. Optics letters, 34(23), 3665--3667.
• Chen, S., Zang, W., Schülzgen, A., Liu, X., Tian, J., Moloney, J. V., & Peyghambarian, N. (2009). Modeling of Z-scan characteristics for one-dimensional nonlinear photonic bandgap materials. Optics Letters, 34(23), 3665-3667.
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  PMID: 19953155;Abstract: We propose a Z-scan theory for one-dimensional nonlinear photonic bandgap materials. The Z-scan characteristics for this material are analyzed. Results show that the Z-scan curves for photonic bandgap materials with nonlinear refraction are similar to those of uniform materials exhibiting both nonlinear refraction and nonlinear absorption simultaneously. Effects of nonlinear absorption on reflected and transmitted Z-scan results are also discussed. © 2009 Optical Society of America.
• Dineen, C., Reichelt, M., Koch, S. W., & Moloney, J. V. (2009). Optical trapping of quantum dots in a metallic nanotrap. Journal of Optics A: Pure and Applied Optics, 11(11).
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  Abstract: We present a novel optical trap structure for the confinement of a freely mobile quantum dot to a sub-diffraction-limited volume. We examine the optical forces on a single quantum dot, under excitonic resonance conditions, in the presence of resonantly enhanced electric fields in the near-field of a suitably engineered metal nanostructure. A numerical scheme to calculate the electromagnetic force on a quantum dot using an adaptive mesh refinement (AMR) FDTD code combined with microscopic material equations is employed. Numerically derived forces on a single quantum dot are presented and it is shown that the dot may be confined in the proposed structure. © 2009 IOP Publishing Ltd.
• Dineen, C., Reichelt, M., Koch, S., & Moloney, J. (2009). Optical trapping of quantum dots in a metallic nanotrap. Journal of Optics A: Pure and Applied Optics, 11(11), 114004.
• Hader, J., Moloney, J. V., Koch, S. W., Vurgaftman, I., & Meyer, J. R. (2009). Microscopic analysis of mid-infrared type-II "w" diode lasers. Applied Physics Letters, 94(6).
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  Abstract: Mid-infrared diode lasers with type-II "W" active regions are analyzed using a fully microscopic many-body theory. The Auger carrier losses are found to dominate over radiative losses even at low temperatures. The experimentally observed strong temperature-dependent increase in Auger losses is shown to be a consequence of thermal gain reduction causing increased threshold carrier densities. Good agreement between theory and experiment is demonstrated for temperature-dependent photoluminescence spectra as well as threshold loss currents. © 2009 American Institute of Physics.
• Hader, J., Moloney, J. V., Rubel, O., Zhang, W., Ackemann, T., & Koch, S. W. (2009). Quantum modelling of semiconductor gain materials and vertical-external-cavity surface-emitting laser systems. physica status solidi.
• Hader, J., Moloney, J., Koch, S., Vurgaftman, I., & Meyer, J. (2009). Microscopic analysis of mid-infrared type-II “W” diode lasers. Applied Physics Letters, 94(6), 061106.
• K\"uhn, E., Thr\"anhardt, A., B\"uckers, C., Koch, S. W., Hader, J., & Moloney, J. (2009). Numerical study of the influence of an antireflection coating on the operating properties of vertical-external-cavity surface-emitting lasers. Journal of Applied Physics, 106(6), 063105.
• Kaneda, Y., Fallahi, M., Hader, J., Moloney, J. V., Koch, S. W., Kunert, B., & Stoltz, W. (2009). Continuous-wave single-frequency 295 nm laser source by a frequency-quadrupled optically pumped semiconductor laser. Optics Letters, 34(22), 3511-3513.
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  PMID: 19927194;Abstract: Up to 136 mW of cw single-frequency output at 295 nm was obtained from a frequency-quadrupled optically pumped semiconductor laser. The highly strained InGaAs quantum-well semiconductor laser operates at 1178 nm in a single frequency. The single-frequency intracavity-doubled 589 nm output is further converted to 295 nm in an external resonator using β-BaB2O 4. © 2009 Optical Society of America.
• Kaneda, Y., Fallahi, M., Hader, J., Moloney, J. V., Koch, S. W., Kunert, B., & Stoltz, W. (2009). Continuous-wave single-frequency 295 nm laser source by a frequency-quadrupled optically pumped semiconductor laser. Optics letters, 34(22), 3511--3513.
• Kolesik, M., Faccio, D., Wright, E., Di Trapani, P., & Moloney, J. (2009). Supercontinuum generation in planar glass membrane fibers: comparison with bulk media. Optics letters, 34(3), 286--288.
• Kühn, E., Thränhardt, A., Bückers, C., Koch, S. W., Hader, J., & Moloney, J. V. (2009). Numerical study of the influence of an antireflection coating on the operating properties of vertical-external-cavity surface-emitting lasers. Journal of Applied Physics, 106(6).
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  Abstract: The influence of an antireflection coating on the input-output power characteristics and the switch-on dynamics of a vertical-external-cavity surface-emitting laser is investigated numerically with an effective rate-equation simulation based on microscopic many-body calculations for the optical gain/absorption and carrier losses. The simulations show a significantly higher threshold and a slower switch-on dynamics for the antireflection coated devices. These differences are caused by a reduction in the mode amplitude at the position of the active medium due to a less pronounced subcavity. © 2009 American Institute of Physics.
• Laubsch, A., Sabathil, M., Bergbauer, W., Strassburg, M., Lugauer, H., Peter, M., Lutgen, S., Linder, N., Streubel, K., Hader, J., & others, . (2009). On the origin of IQE-‘droop’in InGaN LEDs. physica status solidi (c), 6(S2), S913--S916.
• Laubsch, A., Sabathil, M., Bergbauer, W., Strassburg, M., Lugauer, H., Peter, M., Lutgen, S., Linder, N., Streubel, K., Hader, J., Moloney, J. V., Pasenow, B., & Koch, S. W. (2009). On the origin of IQE-'droop' in InGaN LEDs. Physica Status Solidi (C) Current Topics in Solid State Physics, 6(SUPPL. 2), S913-S916.
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  Abstract: We identify a quantum well internal high density Augerlike loss process as the origin of the so called 'droop' of internal quantum efficiency (IQE) in InGaN based light emitters. The IQE of such a device peaks at small current densities and then monotonously decreases towards higher currents. The origin of this 'droop' has been widely discussed recently and many possible mechanisms have been proposed for explaining the effect. We compare temperature and carrier density dependent electroluminescence and photoluminescence measurements of a green emitting single quantum-well (SQW) LED over a wide parameter range. The carrier-density as well as temperature dependence of efficiency is identical in both measurements, indicating that the decrease is due to a high density quantum-well internal loss process. The data can be accurately modeled assuming an Auger-like loss process with C = 3.5 × 10-31 cm6s-1. We suggest phonon- or defect-assisted Auger recombination as the origin of this loss-channel. The high current performance can be improved if a thick InGaN SQW or a multi quantum-well (MQW) is used. This is in very good agreement with theoretical simulations. © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
• Liu, J., Brio, M., & Moloney, J. V. (2009). A diagonal split-cell model for the overlapping Yee FDTD method. Acta Mathematica Scientia, 29(6), 1670--1676.
• Liu, J., Brio, M., & Moloney, J. V. (2009). Overlapping Yee FDTD method on nonorthogonal grids. Journal of Scientific Computing, 39(1), 129--143.
• Love, D., Kolesik, M., & Moloney, J. V. (2009). Optimization of ultrashort pulse generation in passively mode-locked vertical external-cavity semiconductor lasers. IEEE Journal of Quantum Electronics, 45(5), 439-445.
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  Abstract: We present a genetic algorithm based method to optimize the gain medium design of a passively mode-locked vertical external-cavity surface-emitting laser (VECSEL) for ultrashort pulse generation. Beginning with a given standard VECSEL design, we show that a simple modification to the DBR within the active mirror can significantly reduce both the duration and the chirp of the generated pulse. We demonstrate, using realistic numerical simulations, that the full-width at half-maximum of the pulse can be reduced by more than a factor of two. The required design changes come at the cost of increased sensitivity to perturbations in the active chip growth. Methods of counteracting this trend are presented. © 2009 IEEE.
• Love, D., Kolesik, M., & Moloney, J. V. (2009). Optimization of ultrashort pulse generation in passively mode-locked vertical external-cavity semiconductor lasers. Quantum Electronics, IEEE Journal of, 45(5), 439--445.
• Mansuripur, M., Zakharian, A. R., Lesuffleur, A., Oh, S., Jones, R. J., Lindquist, N. C., Hyungsoon, I. m., Kobyakov, A., & Moloney, J. V. (2009). Plasmonic nano-structures for optical data storage. Optics Express, 17(16), 14001-14014.
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  PMID: 19654809;Abstract: We propose a method of optical data storage that exploits the small dimensions of metallic nano-particles and/or nano-structures to achieve high storage densities. The resonant behavior of these particles (both individually and in small clusters) in the presence of ultraviolet, visible, and near-infrared light may be used to retrieve pre-recorded information by far-field spectroscopic optical detection. In plasmonic data storage, a very short (∼ few femtoseconds) laser pulse is focused to a diffraction-limited spot over a small region of an optical disk containing metallic nano-structures. The digital data stored in each bit-cell, comprising multiple bits of information, modifies the spectrum of the incident light pulse. This spectrum is subsequently detected, upon reflection/transmission, with the aid of an optical spectrum analyzer. We present theoretical as well as preliminary experimental results that confirm the potential of plasmonic nano-structures for high-density optical data storage applications. © 2009 Optical Society of America.
• Mansuripur, M., Zakharian, A., Lesuffleur, A., Oh, S., Jones, R., Lindquist, N., Im, H., Kobyakov, A., & Moloney, J. (2009). Plasmonic nano-structures for optical data storage. Optics express, 17(16), 14001--14014.
• Moloney, J. V., Hader, J., Laubsch, A., Sabathil, M., Bergbauer, W., Strassburg, M., Lugauer, H., Peter, M., Lutgen, S., Linder, N., Streubel, K., Pasenow, B., & Koch, S. W. (2009). On the origin of IQE‐‘droop’ in InGaN LEDs. physica status solidi c, 6(S2). doi:10.1002/pssc.200880950
• Moloney, J. V., Hader, J., Pasenow, B., Koch, S. W., Sabathil, M., Linder, N., & Lutgen, S. (2009). Auger losses in GaN‐based quantum wells: Microscopic theory. physica status solidi c, 6(S2). doi:10.1002/pssc.200880865
• Moloney, J. V., Kolesik, M., Polynkin, P., Siviloglou, G. A., & Christodoulides, D. N. (2009). Curved Plasma Channel Generation Using Ultraintense Airy Beams. Science, 324(5924), 229-232. doi:10.1126/science.1169544
• Pasenow, B., Koch, S. W., Hader, J., Moloney, J. V., Sabathil, M., Linder, N., & Lutgen, S. (2009). Auger losses in GaN-based quantum wells: Microscopic theory. Physica Status Solidi (C) Current Topics in Solid State Physics, 6(SUPPL. 2), S864-S868.
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  Abstract: Fully microscopic many-body models are used to study the importance of radiative and Auger carrier losses in InGaN/GaN quantum wells. Since the usual direct bandto-band Auger losses are too small to explain the experimentally observed droop of the external quantumefficiency in such structures, phonon assisted Auger processes are discussed. First numerical estimates indicate that the resulting losses constitute an important intrinsic loss process in InGaN/GaN quantum wells. © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
• Pasenow, B., Koch, S., Hader, J., Moloney, J., Sabathil, M., Linder, N., & Lutgen, S. (2009). Auger losses in GaN-based quantum wells: Microscopic theory. physica status solidi (c), 6(S2), S864--S868.
• Polynkin, P., Kolesik, M., & Moloney, J. (2009). Extended filamentation with temporally chirped femtosecond Bessel-Gauss beams in air. Optics Express, 17(2), 575-584.
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  PMID: 19158870;Abstract: We report experimental results on ultrafast filamentation with temporally chirped femtosecond Bessel-Gauss beams. We find that by chirping the pulses, the longitudinal range of the generated plasma channels can be extended relative to filaments generated by fully compressed, transform-limited femtosecond pulses. We find a clear correlation between the extent of filamentation and the intensity of the on-axis emission by the femtosecond Bessel-Gauss beam. The on-axis emission is negligible for fully compressed pulses, but it can become quite substantial (up to 10% of the input pulse energy) when chirped pulses are used. Under certain conditions, the on-axis emission becomes sufficient for generating its own plasma channel thus resulting in extended filamentation. This effect may offer means of remote control over filament formation with femtosecond Bessel-Gauss beams. We identify a four-wave mixing process, enhancement of which is likely to result in a maximum of the on-axis emission, and derive a simple expression for estimating the duration of the chirped pulse that is required for such enhancement. Our estimations are in good agreement with the experiment. © 2009 Optical Society of America.
• Polynkin, P., Kolesik, M., & Moloney, J. (2009). Extended filamentation with temporally chirped femtosecond Bessel-Gauss beams in air. Optics express, 17(2), 575--584.
• Polynkin, P., Kolesik, M., & Moloney, J. (2009). Filamentation of Femtosecond Laser Airy Beams in Water. Physical Review Letters, 103(12).
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  Abstract: We report experiments on the propagation of intense, femtosecond, self-bending Airy laser beams in water. The supercontinuum radiation generated along the curved beam path is angularly resolved in the far field. Spectral maps of this radiation reveal the changing character of the laser-pulse evolution on propagation. © 2009 The American Physical Society.
• Polynkin, P., Kolesik, M., & Moloney, J. (2009). Filamentation of femtosecond laser Airy beams in water. Physical review letters, 103(12), 123902.
• Polynkin, P., Kolesik, M., Moloney, J. V., Siviloglou, G. A., & Christodoulides, D. N. (2009). Curved plasma channel generation using ultraintense Airy beams. Science, 324(5924), 229--232.
• Polynkin, P., Kolesik, M., Moloney, J. V., Siviloglou, G. A., & Christodoulides, D. N. (2009). Curved plasma channel generation using ultraintense airy beams. Science, 324(5924), 229-232.
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  PMID: 19359582;Abstract: Plasma channel generation (or filamentation) using ultraintense laser pulses in dielectric media has a wide spectrum of applications, ranging from remote sensing to terahertz generation to lightning control. So far, laser filamentation has been triggered with the use of ultrafast pulses with axially symmetric spatial beam profiles, thereby generating straight filaments. We report the experimental observation of curved plasma channels generated in air using femtosecond Airy beams. In this unusual propagation regime, the tightly confined main intensity feature of the axially nonsymmetric laser beam propagates along a bent trajectory, leaving a curved plasma channel behind. Secondary channels bifurcate from the primary bent channel at several locations along the beam path. The broadband radiation emanating from different longitudinal sections of the curved filament propagates along angularly resolved trajectories.
• Polynkin, P., Kolesik, M., Moloney, J., Siviloglou, G., & Christodoulides, D. (2009). Curved Plasma Channel Generation in Air Using Ultra-Intense Self-Bending Airy Beams. Optics and Photonics News, 20(12), 28--28.
• Rotter, T. J., Tatebayashi, J., Senanayake, P., Balakrishnan, G., Rattunde, M., Wagner, J., Hader, J., Moloney, J. V., Koch, S. W., Dawson, L. R., & Huffaker, D. L. (2009). Continuous-wave room-temperature operation of 2-μm sb-based optically-pumped vertical-external-cavity surface-emitting laser monolithically grown on GaAs substrates. Applied Physics Express, 2(11).
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  Abstract: We report on continuous-wave room-temperature operation at 2.014 μm of Sb-based optically-pumped vertically-external-cavity surface-emitting lasers monolithically grown on GaAs substrates by using an interfacial misfit (IMF) growth mode. The IMF is characterized by a periodic array of 90° misfit dislocation and enables the relaxed GaSb growth with a low dislocation density on lattice-mismatched GaAs after the growth of only a few monolayers of GaSb. A maximum output power of >100 mW is obtained at -5°C. © 2009 The Japan Society of Applied Physics.
• Rotter, T. J., Tatebayashi, J., Senanayake, P., Balakrishnan, G., Rattunde, M., Wagner, J., Hader, J., Moloney, J. V., Koch, S. W., Dawson, L. R., & others, . (2009). Continuous-Wave, Room-Temperature Operation of 2-$\mu$m Sb-Based Optically-Pumped Vertical-External-Cavity Surface-Emitting Laser Monolithically Grown on GaAs Substrates. Applied physics express, 2(11), 112102.
• Walton, M., Terry, N., Hader, J., Moloney, J., & Bedford, R. (2009). Extraction of semiconductor microchip differential gain by use of optically pumped semiconductor laser. Applied Physics Letters, 95(11), 111101.
• Walton, M., Terry, N., Hader, J., Moloney, J., & Bedford, R. (2009). Extraction of semiconductor microchip differential gain by use of optically pumped semiconductor laser. Applied Physics Letters, 95(11).
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  Abstract: The small-signal modulation response of a vertical external cavity surface emitting laser is analyzed to determine its resonance frequency in relation to photon density, allowing nondestructive extraction of characteristic parameters of chips, such as internal loss and differential gain. © 2009 American Institute of Physics.
• Wang, J., Zeng, Y., Chen, X., Lu, W., & Moloney, J. V. (2009). Various mechanisms for efficient optical transmission through bilayered subwavelength patterned metal films. JOSA B, 26(12), B7--B10.
• Wang, J., Zeng, Y., Chen, X., Wei, L. u., & Moloney, J. V. (2009). Various mechanisms for efficient optical transmission through bilayered subwavelength patterned metal films. Journal of the Optical Society of America B: Optical Physics, 26(12), B7-B10.
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  Abstract: Light transmission through bilayered thin metal films perforated with subwavelength hole arrays are numerically studied based on a full-vector finite-difference time-domain approach. A variety of transmission peaks originating from different physical mechanisms are observed. In addition to the direct tunneling and Fabry-Pèrot resonances, generally possessed by idealized bilayered dielectric slabs, the near-field localized plasmon polaritons also play important roles. They not only influence the direct tunneling in a destructive or constructive way, but the interactions between these localized plasmon polaritons on both metal films also result in additional channels that transfer optical energy effectively. © 2009 Optical Society of America.
• Yarborough, J. M., Lai, Y., Kaneda, Y., Hader, J., Moloney, J. V., Rotter, T. J., Balakrishnan, G., Hains, C., Huffaker, D., Koch, S. W., & Bedford, R. (2009). Record pulsed power demonstration of a 2 μm GaSb-based optically pumped semiconductor laser grown lattice-mismatched on an AlAs/GaAs Bragg mirror and substrate. Applied Physics Letters, 95(8).
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  Abstract: An optically pumped semiconductor laser resonant periodic gain structure, grown lattice-mismatched on an AlAs/GaAs Bragg mirror, exhibits a peak pulsed power of 70 W when pumped with a pulsed 1064 nm neodymium doped yttrium aluminum garnet laser. © 2009 American Institute of Physics.
• Yarborough, J., Lai, Y., Kaneda, Y., Hader, J., Moloney, J. V., Rotter, T., Balakrishnan, G., Hains, C., Huffaker, D., Koch, S., & others, . (2009). Record pulsed power demonstration of a 2 $\mu$m GaSb-based optically pumped semiconductor laser grown lattice-mismatched on an AlAs/GaAs Bragg mirror and substrate. Applied Physics Letters, 95(8), 081112.
• Zeng, Y., & Moloney, J. V. (2009). Polarization-current-based, finite-difference time-domain, near-to-far-field transformation. Optics Letters, 34(10), 1600-1602.
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  PMID: 19448834;Abstract: A near-to-far-field transformation algorithm for three-dimensional finite-difference time-domain is presented in this Letter. This approach is based directly on the polarization current of the scatterer, not the scattered near fields. It therefore eliminates the numerical errors originating from the spatial offset of the E and H fields, inherent in the standard near-to-far-field transformation. The proposed method is validated via direct comparisons with the analytical Lorentz-Mie solutions of plane waves scattered by large dielectric and metallic spheres with strong forward-scattering lobes. © 2009 Optical Society of America.
• Zeng, Y., & Moloney, J. V. (2009). Polarization-current-based, finite-difference time-domain, near-to-far-field transformation. Optics letters, 34(10), 1600--1602.
• Zeng, Y., & Moloney, J. V. (2009). Volume electric dipole origin of second-harmonic generation from metallic membrane with noncentrosymmetric patterns. Optics letters, 34(18), 2844--2846.
• Zeng, Y., & Moloney, J. V. (2009). Volume electric dipole origin of second-harmonic generation from metallic membrane with none entro symmetric patterns. Optics Letters, 34(18), 2844-2846.
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  PMID: 19756124;Abstract: We analytically study second-harmonic (SH) generation from thin metallic films with subwavelength noncentrosymmetric patterns. Because the thickness of the film is much smaller than the SH wavelength, retardation effects are negligible. The far-field SH intensities are thus dominated by an effective electric dipole. It is further demonstrated that internal bulk SH polarization density is comparable with its surface counterpart. The electric dipole, consequently, originates from the entire volume of the metallic membrane. © 2009 Optical Society of America.
• Zeng, Y., Hoyer, W., Liu, J., Koch, S. W., & Moloney, J. V. (2009). Classical theory for second-harmonic generation from metallic nanoparticles. Physical Review B - Condensed Matter and Materials Physics, 79(23).
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  Abstract: In this paper, we develop a classical electrodynamic theory to study the optical nonlinearities of metallic nanoparticles. The quasi free electrons inside the metal are approximated as a classical Coulomb-interacting electron gas, and their motion under the excitation of an external electromagnetic field is described by the plasma equations. This theory is further tailored to study second-harmonic generation. Through detailed experiment-theory comparisons, we validate this classical theory as well as the associated numerical algorithm. It is demonstrated that our theory not only provides qualitative agreement with experiments but it also reproduces the overall strength of the experimentally observed second-harmonic signals. © 2009 The American Physical Society.
• Zeng, Y., Hoyer, W., Liu, J., Koch, S. W., & Moloney, J. V. (2009). Classical theory for second-harmonic generation from metallic nanoparticles. Physical Review B, 79(23), 235109.
• Zhu, X., Schulzgen, A., Li, H., Li, L., Temyanko, V., Moloney, J., & Peyghambarian, N. (2009). High-power fiber lasers and amplifiers based on multimode interference. Selected Topics in Quantum Electronics, IEEE Journal of, 15(1), 71--78.
• Zhu, X., Schülzgen, A., Li, H., Li, L., Temyanko, V. L., Moloney, J. V., & Peyghambarian, N. (2009). High-power fiber lasers and amplifiers based on multimode interference. IEEE Journal on Selected Topics in Quantum Electronics, 15(1), 71-78.
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  Abstract: In this paper, high-power fiber lasers and amplifiers based on multimode interference (MMI) in active large-core multimode optical fibers are proposed and their properties are investigated. Experimental results and simulations indicate that such fiber lasers and amplifiers are promising candidates for high-power miniature solid-state lasers. Utilization of the MMI leads to remarkable spectral and spatial features of fiber lasers and amplifiers such as generation of high-power diffraction-free beams. © 2006 IEEE.
• Averchi, A., Faccio, D., Berlasso, R., Kolesik, M., Moloney, J. V., Couairon, A., & Di Trapani, P. (2008). Phase matching with pulsed Bessel beams for high-order harmonic generation. Physical Review A, 77(2), 021802.
• Averchi, A., Faccio, D., Berlasso, R., Kolesik, M., Moloney, J. V., Couairon, A., & Trapani, P. D. (2008). Phase matching with pulsed Bessel beams for high-order harmonic generation. Physical Review A - Atomic, Molecular, and Optical Physics, 77(2).
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  Abstract: We propose a different approach to obtain phase-matched generation of high-order harmonics based on the use of pulsed Bessel beams as pump pulses. By means of the “coherence mapa technique, we show that it is possible to maximize the generation of a chosen harmonic of interest by properly adjusting the phase front tilt of the pulsed Bessel beam to compensate the mismatch arising from material and plasma dispersion and atomic phase. © 2008 The American Physical Society.
• B\"uckers, C., Thr\"anhardt, A., Koch, S., Rattunde, M., Schulz, N., Wagner, J., Hader, J., & Moloney, J. (2008). Microscopic calculation and measurement of the laser gain in a (GaIn) Sb quantum well structure. Applied Physics Letters, 92(7), 071107.
• Bueckers, C., Thraenhardt, A., Koch, S. W., Hader, J., Moloney, J. V., Rattunde, M., Schulz, N., & Wagner, J. (2008). Laser properties of (GaIn) Sb heterostructures-a microscopic evaluation.
• Bückers, C., Thränhardt, A., Koch, S. W., Rattunde, M., Schulz, N., Wagner, J., Hader, J., & Moloney, J. V. (2008). Microscopic calculation and measurement of the laser gain in a (GaIn)Sb quantum well structure. Applied Physics Letters, 92(7).
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  Abstract: A detailed microscopic calculation and experimental measurements of the optical gain from a (GaIn)Sb structure are presented. For a given excitation density, the gain in the (GaIn)Sb material system considerably exceeds that of a comparable equivalent (GaIn) AsGaAs structure. The physical reasons for this high gain are analyzed and attributed mostly to band structure effects. © 2008 American Institute of Physics.
• Chen, S., Han, L., Sch\vRlzgen, A., Li, H., Li, L., Moloney, J. V., & Peyghambarian, N. (2008). Local electric field enhancement and polarization effects in a surface-enhanced Raman scattering fiber sensor with chessboard nanostructure. Optics express, 16(17), 13016--13023.
• Chen, S., Han, L., Schülzgen, A., Hongbo, L. i., Li, L. i., Moloney, J. V., & Peyghambarian, N. (2008). Local electric field enhancement and polarization effects in a surface-enhanced Raman scattering fiber sensor with chessboard nanostructure. Optics Express, 16(17), 13016-13023.
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  PMID: 18711540;Abstract: A surface-enhanced Raman scattering fiber Hensor with chessboard nanostructure on a cleaved fiber facet is studied by finitedifference time-domain method. Surface plasmons at the metal coated nanostructured fiber facet can be effectively excited and strong local electric field enhancement is obtained. Studies on the influence of light polarization demonstrate a large polarization dependence of the field enhancement factor while the polarization effects on the plasmon resonance wavelength are relatively small. © 2008 Optical Society of America.
• Chen, S., Zang, W., Sch\"ulzgen, A., Liu, J., Han, L., Zeng, Y., Tian, J., Song, F., Moloney, J. V., & Peyghambarian, N. (2008). Implicit high-order unconditionally stable complex envelope algorithm for solving the time-dependent Maxwell's equations. Optics letters, 33(23), 2755--2757.
• Chen, S., Zang, W., Schülzgen, A., Liu, J., Han, L., Zeng, Y., Tian, J., Song, F., Moloney, J. V., & Peyghambarian, N. (2008). Implicit high-order unconditionally stable complex envelope algorithm for solving the time-dependent Maxwell's equations. Optics Letters, 33(23), 2755-2757.
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  PMID: 19037416;Abstract: Based on the Padé approximation and multistep method, we propose an implicit high-order unconditionally stable complex envelope algorithm to solve the time-dependent Maxwell's equations. Unconditional numerical stability can be achieved simultaneously with a high-order accuracy in time. As we adopt the complex envelope Maxwell's equations, numerical dispersion and dissipation are very small even at comparatively large time steps. To verify the capability of our algorithm, we compare the results of the proposed method with the exact solutions. © 2008 Optical Society of America.
• Faccio, D., Averchi, A., Lotti, A., Kolesik, M., Moloney, J. V., Couairon, A., & Trapani, P. D. (2008). Generation and control of extreme blueshifted continuum peaks in optical Kerr media. Physical Review A - Atomic, Molecular, and Optical Physics, 78(3).
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  Abstract: We demonstrate tunable, extremely blueshifted continuum in λ=1.055 μm ultrashort laser pulse filamentation in silica. Close to threshold, the continuum appears as a single, isolated blue peak. The spectral position of the two supercontinuum components can be tuned and a regime with encompassing fundamental and second harmonic is possible to achieve. At higher energies, the continuum expands in bandwidth starting from the blue peak. The spectral dynamics and tunability are explained in terms of X -wave generation and intrafilament pulse splitting which may be controlled by modifying the input pulse focusing conditions. © 2008 The American Physical Society.
• Faccio, D., Averchi, A., Lotti, A., Kolesik, M., Moloney, J., Couairon, A., & Di Trapani, P. (2008). Generation and control of extreme blueshifted continuum peaks in optical Kerr media. Physical Review A, 78(3), 033825.
• Faccio, D., Lotti, A., Kolesik, M., Moloney, J. V., Tzortzakis, S., Couairon, A., & Trapani, P. D. (2008). Spontaneous emergence of pulses with constant carrier-envelope phase in femtosecond filamentation. Optics Express, 16(15), 11103-11114.
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  PMID: 18648424;Abstract: We study the possibility to obtain high-intensity pulses that maintain a constant Carrier Envelope Phase (CEP) during propagation in dispersive media, i.e. pulses such that the carrier-wave offset with respect to the main intensity peak remains fixed. Our numerical experiments strongly suggest that pulse splitting and X-wave formation within femtosecond laser pulse filamentation leads to the formation of "constant-CEP" within well-defined regions inside the filament. We study the creation of "constantCEP" pulses in both gasseous and condensed media showing that this is a generic feature of filaments. © 2008 Optical Society of America.
• Faccio, D., Lotti, A., Kolesik, M., Moloney, J., Tzortzakis, S., Couairon, A., & Di Trapani, P. (2008). Spontaneous emergence of pulses with constant carrier-envelope phase in femtosecond filamentation. Optics express, 16(15), 11103--11114.
• Fallahi, M., Fan, L., Kaneda, Y., Hessenius, C., Hader, J., Hongbo, L. i., Moloney, J. V., Kunert, B., Stolz, W., Koch, S. W., Murray, J., & Bedford, R. (2008). 5-W yellow laser by intracavity frequency doubling of high-power vertical-external-cavity surface-emitting laser. IEEE Photonics Technology Letters, 20(20), 1700-1702.
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  Abstract: We report on the development of a high-power tunable yellow-orange laser. It is based on intracavity frequency doubling of a widely tunable, highly strained InGaAs-GaAs vertical-external-cavity surface-emitting laser operating near 1175 nm. Over 5 W of continuous-wave output power is achieved and is tunable over a 15-nm band centered at 587 nm. This compact low-cost high-power yellow-orange laser provides an innovative alternative for sodium guidestar lasers, medical and communication applications. © 2008 IEEE.
• Fallahi, M., Fan, L., Kaneda, Y., Hessenius, C., Hader, J., Li, H., Moloney, J. V., Kunert, B., Stolz, W., Koch, S. W., & others, . (2008). 5-W yellow laser by intracavity frequency doubling of high-power vertical-external-cavity surface-emitting laser. Photonics Technology Letters, IEEE, 20(20), 1700--1702.
• Feth, N., Linden, S., Klein, M. W., Decker, M., Niesler, F. B., Zeng, Y., Hoyer, W., Liu, J., Koch, S. W., Moloney, J. V., & Wegener, M. (2008). Second-harmonic generation from complementary split-ring resonators. Optics Letters, 33(17), 1975-1977.
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  PMID: 18758583;Abstract: We present experiments on second-harmonic generation from arrays of magnetic split-ring resonators and arrays of complementary split-ring resonators. In both cases, the fundamental resonance is excited by the incident femtosecond laser pulses under normal incidence, leading to comparably strong second-harmonic signals. These findings are discussed in terms of Babinet's principle and in terms of a recently developed microscopic classical theory that leads to good agreement regarding the relative and the absolute nonlinear signal strengths. The hydrodynamic convective contribution is found to be the dominant source of second-harmonic generation - in contrast to a previous assignment [Science 313, 502 (2006)]. © 2008 Optical Society of America.
• Feth, N., Linden, S., Klein, M., Decker, M., Niesler, F., Zeng, Y., Hoyer, W., Liu, J., Koch, S., Moloney, J., & others, . (2008). Second-harmonic generation from complementary split-ring resonators. Optics letters, 33(17), 1975--1977.
• Hader, J., Koch, S. W., & Moloney, J. V. (2008). Quantum Design of Active Semiconductor Materials for Targeted Wavelengths. MRS Proceedings, 1076(1), 97-117. doi:10.1557/proc-1076-k07-04
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  Performance metrics of every class of semiconductor amplifier or laser system depend critically on semiconductor QW optical properties such as photoluminescence (PL), gain and recombination losses (radiative and nonradiative). Current practice in amplifier or laser design assumes phenomenological parameterized models for these critical optical properties and has to rely on experimental measurement to extract model fit parameters. In this tutorial, I will present an overview of a powerful and sophisticated first-principles quantum design approach that allows one to extract these critical optical properties without relying on prior experimental measurement. It will be shown that an end device L-I characteristic can be predicted with the only input being intrinsic background losses, extracted from cut-back experiments. We will show that textbook and literature models of semiconductor amplifiers and lasers are seriously flawed.
• Hader, J., Moloney, J. V., & Koch, S. W. (2008). Temperature dependence of radiative and Auger losses in quantum wells. IEEE Journal of Quantum Electronics, 44(2), 185-191.
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  Abstract: Fully microscopic models are used to study the temperature dependence of carrier losses due to radiative and Auger recombination processes in semiconductor quantum wells. The temperature (T) dependence of these loss processes is shown to depend on the carrier density, on details of the bandstructure, and on the Coulomb effects. While classical estimates based on simplified models predict a density independent 1/T-variation of the radiative losses, we find for the example of typical 1.3 μ InGaAsP structures a dependence closer to 1/T3 at low densities. At high densities the temperature dependence is much weaker and can no longer be described by a simple power law. For a given density the Auger losses can be described by an exponential temperature dependence for limited temperature ranges if one uses a density dependent activation energy that can take positive or negative values. © 2007 IEEE.
• Hader, J., Moloney, J. V., & Koch, S. W. (2008). Temperature dependence of radiative and Auger losses in quantum wells. Quantum Electronics, IEEE Journal of, 44(2), 185--191.
• Hader, J., Moloney, J. V., Pasenow, B., Koch, S. W., Sabathil, M., Linder, N., & Lutgen, S. (2008). On the importance of radiative and Auger losses in GaN-based quantum wells. Applied Physics Letters, 92(26).
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  Abstract: Fully microscopic many-body models are used to study the importance of radiative and Auger carrier losses in InGaNGaN quantum wells. Auger losses are found to be negligible in contrast to recent speculations on their importance for the experimentally observed efficiency droop. Good agreement with experimentally measured threshold losses is demonstrated. The results show no significant dependence on details of the well alloy profile. © 2008 American Institute of Physics.
• Hader, J., Moloney, J., Pasenow, B., Koch, S., Sabathil, M., Linder, N., & Lutgen, S. (2008). On the importance of radiative and Auger losses in GaN-based quantum wells. Applied Physics Letters, 92(26), 261103.
• Hessenius, C., Fallahi, M., Hader, J., Moloney, J. V., Stolz, W., Li, H., Koch, S. W., Hessenius, C., Fan, L., & Fallahi, M. (2008). Highly strained InGaAs/GaAs vertical-external-cavity surface-emitting laser for the generation of coherent yellow-orange light. Proceedings of SPIE, 6871. doi:10.1117/12.763529
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  Optically pumped semiconductor vertical-external-cavity surface-emitting laser (VECSEL) potentially provides an innovative approach to low-cost frequency agile lasers engineered for specific applications in infrared and visible range. In this paper, we report on the development and demonstration of a multi-Watt highly strained InGaAs/ GaAs vertical-external- cavity surface-emitting laser (VECSEL), which can be tuned from 1147 nm to 1197 nm. Based on this tunable InGaAs/GaAs VECSEL and intracavity frequency doubling, we develop multi-Watt frequency-doubled tunable VECSEL in a wide yellow-orange band (579 ~595 nm). This compact high-power yellow-orange laser provides an innovative approach to an affordable guidestar laser (~589.1 nm) solution, and has a lot of important applications in biomedicine.
• Imhof, S., B\"uckers, C., Thr\"anhardt, A., Hader, J., Moloney, J., & Koch, S. (2008). Microscopic theory of the optical properties of Ga (AsBi)/GaAs quantum wells. Semiconductor Science and Technology, 23(12), 125009.
• Imhof, S., Bückers, C., Thränhardt, A., Hader, J., Moloney, J. V., & Koch, S. W. (2008). Microscopic theory of the optical properties of Ga(AsBi)/GaAs quantum wells. Semiconductor Science and Technology, 23(12).
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  Abstract: Optical gain and photoluminescence as well as radiative and Auger losses are calculated for Ga(AsBi)/GaAs quantum wells. The results are obtained using a consistent microscopic theory and an anticrossing model for the band structure. The influence of the band structure parameters on the optical properties is investigated. © 2008 IOP Publishing Ltd.
• Jeffries, G. D., Jeong, E., Lim, Y. J., Chin, M. H., Kim, J. H., Lee, S. H., Ji, S. H., Lee, G., Park, K. H., Choi, H. C., & others, . (2008). LASERS, OPTICS, AND OPTOELECTRONICS. Appl. Phys. Lett, 92(26).
• Kaneda, Y., Yarborough, J. M., Li, L. i., Peyghambarian, N., Fan, L., Hessenius, C., Fallahi, M., Hader, J., Moloney, J. V., Honda, Y., Nishioka, M., Shimizu, Y., Miyazono, K., Shimatani, H., Yoshimura, M., Mori, Y., Kitaoka, Y., & Sasaki, T. (2008). Continuous-wave all-solid-state 244 nm deep-ultraviolet laser source by fourth-harmonic generation of an optically pumped semiconductor laser using CsLiB₆O₁₀ in an external resonator. Optics Letters, 33(15), 1705-1707.
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  PMID: 18670510;Abstract: We report an all-solid-state laser system that generates over 200 mW cw at 244 nm. An optically pumped semiconductor laser is internally frequency doubled to 488 nm. The 488 nm output is coupled to an external resonator, where it is converted to 244 nm using a CsLiB6O10 (CLBO) crystal. The output power is limited by the available power at 488 nm, and no noticeable degradation in output power was observed over a period of several hours. © 2008 Optical Society of America.
• Kaneda, Y., Yarborough, J., Li, L., Peyghambarian, N., Fan, L., Hessenius, C., Fallahi, M., Hader, J., Moloney, J. V., Honda, Y., & others, . (2008). Continuous-wave all-solid-state 244 nm deep-ultraviolet laser source by fourth-harmonic generation of an optically pumped semiconductor laser using CsLiB< sub> 6 O< sub> 10 in an external resonator. Optics letters, 33(15), 1705--1707.
• Kolesik, M., & Moloney, J. (2008). Perturbative and non-perturbative aspects of optical filamentation in bulk dielectric media. Optics express, 16(5), 2971--2988.
• Kolesik, M., & Moloney, J. V. (2008). Perturbative and non-perturbative aspects of optical filamentation in bulk dielectric media. Optics Express, 16(5), 2971-2988.
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  PMID: 18542383;Abstract: The field of optical filament formation from initial ultrashort laser pulses in bulk dielectric media has now reached a high state of maturity, and has been studied in all three phases of matter, including long distance propagation in air, also termed light string propagation, water, and glass. From the earliest studies of light string propagation in air it was observed that conical emission, namely colored light emission off-axis from the filament, was a byproduct that accompanied the filamentation process. Since then several other byproducts accompanying optical filamentation have been studied, namely, white light or supercontinuum (SC) generation, third-harmonic (TH) generation, and X- and O-waves. Our goal in this paper is to review the theory and simulation of the byproducts accompanying optical filamentation, and to show that a unified approach is possible. Employing the angularly resolved spectrum, or K - Ω spectrum, a notion that has been used to great effect in the area of nonlinear conical waves, we demonstrate that a unified approach to the byproducts accompanying optical filamentation can be achieved using the twin notions of the Effective Three-Wave-Mixing (ETWM) picture of wave-mixing in the presence of filaments, which determines the locus of phase-matched wave generation in the angularly resolved spectrum, and the first-Born approximation to determine the profile of the angularly resolved spectrum. We summarize results of previous works and show that unlike the essentially non-perturbative core of the filament, several byproducts of filamentation can be treated as perturbative effects that have negligible feed-back effects on the filament itself. This should be of great utility for future studies of optimization of the yield of a given byproduct. © 2008 Optical Society of America.
• Li, H., Hader, J., Moloney, J. V., & Koch, S. W. (2008). VECSEL subcavity design and optimization for targeted wavelengths. Proc. of SPIE Vol, 6871, 687110--1.
• Li, L., Sch\"ulzgen, A., Zhu, X., Moloney, J., Albert, J., & Peyghambarian, N. (2008). 1W tunable dual-wavelength emission from cascaded distributed feedback fiber lasers. Applied Physics Letters, 92(5), 051111.
• Li, L., Schülzgen, A., Zhu, X., Moloney, J. V., Albert, J., & Peyghambarian, N. (2008). 1 W tunable dual-wavelength emission from cascaded distributed feedback fiber lasers. Applied Physics Letters, 92(5).
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  Abstract: We present experimental results of cascaded distributed feedback fiber lasers that generate up to 1 W continuous-wave dual-wavelength emission at room temperature. The complete laser device is integrated into a 10-cm -long active phosphate glass fiber with two phase-shifted gratings inscribed. The distributed feedback fiber lasers are cladding pumped by multimode laser diodes, in contrast to conventional core pumping with single-mode diodes. Tuning of the emission wavelength is also demonstrated. © 2008 American Institute of Physics.
• Moloney, J. V., Hader, J., & Koch, S. W. (2008). Quantum design of active semiconductor materials for targeted wavelengths: a predictive design tool for edge emitters and OPSLs. Proceedings of SPIE, 6871. doi:10.1117/12.768525
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  Performance metrics of every class of semiconductor amplifier or laser system depend critically on semiconductor QW optical properties such as photoluminescence (PL), gain and recombination losses (radiative and nonradiative). Current practice in amplifier or laser design assumes phenomenological parameterized models for these critical optical properties and has to rely on experimental measurement to extract model fit parameters. In this tutorial, I will present an overview of a powerful and sophisticated first-principles quantum design approach that allows one to extract these critical optical properties without relying on prior experimental measurement. It will be shown that an end device L-I characteristic can be predicted with the only input being intrinsic background losses, extracted from cut-back experiments. We will show that textbook and literature models of semiconductor amplifiers and lasers are seriously flawed.
• Navarro-Urrios, D., Pitanti, A., Daldosso, N., Gourbilleau, F., Rizk, R., Pucker, G., Pavesi, L., Yamashita, K., Fukuzawa, E., Kitanobou, A., & others, . (2008). LASERS, OPTICS, AND OPTOELECTRONICS. Appl. Phys. Lett, 92(5), 053301.
• Polynkin, P., Kolesik, M., Roberts, A., Faccio, D., Di Trapani, P., & Moloney, J. (2008). Generation of extended plasma channels in air using femtosecond Bessel beams. Optics express, 16(20), 15733--15740.
• Polynkin, P., Kolesik, M., Roberts, A., Faccio, D., Trapani, P. D., & Moloney, J. (2008). Generation of extended plasma channels in air using femtosecond Bessel beams. Optics Express, 16(20), 15733-15740.
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  PMID: 18825212;Abstract: Extending the longitudinal range of plasma channels created by ultrashort laser pulses in atmosphere is important in practical applications of laser-induced plasma such as remote spectroscopy and lightning control. Weakly focused femtosecond Gaussian beams that are commonly used for generating plasma channels offer only a limited control of filamentation. Increasing the pulse energy in this case typically results in creation of multiple filaments and does not appreciably extend the longitudinal range of filamentation. Bessel beams with their extended linear foci intuitively appear to be better suited for generation of long plasma channels. We report experimental results on creating extended filaments in air using femtosecond Bessel beams. By probing the linear plasma density along the filament, we show that apertured Bessel beams produce stable single plasma channels that span the entire extent of the linear focus of the beam. We further show that by temporally chirping the pulse, the plasma channel can be longitudinally shifted beyond the linear-focus zone, an important effect that may potentially offer additional means of controlling filament formation. © 2008 Optical Society of America.
• Polynkin, P., Peyghambarian, N., & Moloney, J. (2008). Efficient energy extraction from large-mode-area, short, heavily Er: Yb codoped phosphate-glass fiber for pulsed laser applications. Applied Physics Letters, 92(6), 061115--061115.
• Polynkin, P., Peyghambarian, N., & Moloney, J. (2008). Efficient energy extraction from large-mode-area, short, heavily Er:Yb codoped phosphate-glass fiber for pulsed laser applications. Applied Physics Letters, 92(6).
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  Abstract: Experimental demonstration of an efficient energy extraction from heavily Er:Yb codoped phosphate-glass fiber is reported. In our experiments, sub- 20-ns pulses at 1.5 μm wavelength produced by an actively Q -switched all-fiber oscillator are amplified in 15 cm long, side-pumped phosphate fiber doped with 1 wt % of Er2 O3 and 8 wt % of Yb2 O3. Two types of active fiber are used, with core diameters of 14 and 25 μm. The pulse energy achieved with these fibers is 105 and 215 μJ, respectively, with nearly diffraction-limited beam quality. These experiments indicate a potential for further energy scaling beyond the millijoule level by increasing the core size of the fiber. © 2008 American Institute of Physics.
• Reichelt, M., Dineen, C., Koch, S. W., & Moloney, J. V. (2008). Optical Forces on a Quantum Dot in Metallic Bowtie Structures. Photonics Technology Letters, IEEE, 20(6), 431--433.
• Reichelt, M., Dineen, C., Koch, S. W., & Moloney, J. V. (2008). Optical forces on a quantum dot in metallic bowtie structures. IEEE Photonics Technology Letters, 20(6), 431-433.
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  Abstract: We present a numerical scheme to calculate the electromagnetic force on a quantum dot in the near-field of subwavelength metallic nano-structures. As an application, we examine the forces on a quantum dot placed in the center of a gold nano-structure. The forces on the quantum dot are calculated using an adaptive mesh refinement finite-difference time-domain code combined with microscopic material equations. Is is shown that the dot may be laterally confined in the proposed geometry. © 2008 IEEE.
• Schafer, M., Hoyer, W., Kira, M., Koch, S. W., & Moloney, J. V. (2008). Influence of dielectric environment on quantum-well luminescence spectra. Journal of the Optical Society of America B: Optical Physics, 25(2), 187-195.
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  Abstract: A fully microscopical theory for the photoluminescence of a quantum-well in an arbitrary one-dimensional stack structure is presented. For strong-coupling configurations, the full semiconductor luminescence equations are solved. For the weak-coupling regime, a frequency-dependent filter function is directly derived from the semiconductor luminescence equations with the knowledge of the dielectric structure. Via that filter function, the detected luminescence can be related to the pure quantum-well emission in vacuum. The approach is generalized to include corrections to the emitted peak width due to the photonic-environment-dependent radiative decay, and the corrections are shown to be obtainable from the mode functions alone. The applicability of the method is thoroughly tested up to the onset of normal-mode coupling. © 2008 Optical Society of America.
• Schafer, M., Hoyer, W., Kira, M., Koch, S., & Moloney, J. (2008). Influence of dielectric environment on quantum-well luminescence spectra. JOSA B, 25(2), 187--195.
• Zeng, Y., Hoyer, W., Liu, J., Koch, S. W., & Moloney, J. V. (2008). Classical theory of second-harmonic generation from magnetic metamaterials. arXiv preprint arXiv:0807.3531.
• Zhu, X., Sch\"ulzgen, A., Li, H., Li, L., Wang, Q., Suzuki, S., Temyanko, V., Moloney, J., & Peyghambarian, N. (2008). Single-transverse-mode output from a fiber laser based on multimode interference. Optics letters, 33(9), 908--910.
• Zhu, X., Sch\vRlzgen, A., Li, H., Li, L., Han, L., Moloney, J., & Peyghambarian, N. (2008). Detailed investigation of self-imaging in large-core multimode optical fibers for application in fiber lasers and amplifiers. Optics express, 16(21), 16632--16645.
• Zhu, X., Schülzgen, A., Li, H., Li, L., Han, L., Moloney, J. V., & Peyghambarian, N. (2008). Detailed investigation of self-imaging in largecore multimode optical fibers for application in fiber lasers and amplifiers. Optics Express, 16(21), 16632-16645.
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  PMID: 18852772;Abstract: Properties of the self-imaging effect based on multimode interference (MMI) in large-core passive optical fibers are investigated and analyzed in detail, with the purpose of using multimode active fibers for high power single-transverse-mode emission. Although perfect self-imaging of the input field from a standard single-mode fiber (SMF-28) in a multimode fiber becomes practically impossible as its core diameter is larger than 50 μm, a quasi-reproduction of the input field occurs when the phase difference between the excited modes and the peak mode inside the multimode fiber is very small. Our simulation and experimental results indicate that, if the length of the multimode fiber segment can be controlled accurately, reproduction of the input field with a self-imaging quality factor larger than 0.9 can be obtained. In this case, a low-loss hybrid fiber cavity composed of a SMF-28 segment and a very-large-core active multimode fiber segment can be built. It is also found that for the hybrid fiber cavity, increasing the mode-field diameter of the single-mode fiber improves both the self-imaging quality and the tolerance on the required length accuracy of the multimode fiber segment. Moreover, in this paper key parameters for the design of MMI-based fiber devices are defined and their corresponding values are provided for multimode fibers with core diameters of 50 μm and 105 μm. © 2008 Optical Society of America.
• B\"uckers, C., Blume, G., Thr\"anhardt, A., Schlichenmaier, C., Klar, P., Weiser, G., Koch, S., Hader, J., Moloney, J., Hosea, T., & others, . (2007). Microscopic electroabsorption line shape analysis for Ga (AsSb)/ GaAs heterostructures. Journal of applied physics, 101(3), 033118.
• Bückers, C., Blume, G., Thränhardt, A., Schlichenmaier, C., Klar, P. J., Weiser, G., Koch, S. W., Hader, J., Moloney, J. V., Hosea, T. J., Sweeney, S. J., Wang, J. -., Johnson, S. R., & Zhang, Y. -. (2007). Microscopic electroabsorption line shape analysis for Ga (AsSb) GaAs heterostructures. Journal of Applied Physics, 101(3).
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  Abstract: A series of Ga (AsSb) GaAs (AlGa) As samples with varying GaAs spacer width are studied by electric-field modulated absorption (EA) and reflectance spectroscopy and modeled using a microscopic theory. The analysis of the Franz-Keldysh oscillations of GaAs capping layer and of the quantum-confined Stark shift of the lowest quantum well (QW) transitions shows the strong inhomogeneity of the built-in electric field indicating that the field modulation due to an external bias voltage differs significantly for the various regions of the structures. The calculations demonstrate that the line shape of the EA spectra of these samples is extremely sensitive to the value of the small conduction band offset between GaAs and Ga (AsSb) as well as to the magnitude of the internal electric field changes caused by the external voltage modulation in the QW region. The EA spectra of the entire series of samples are modeled by the microscopic theory. The good agreement between experiment and theory allows us to extract the strength of the modulation of the built-in electric field in the QW region and to show that the band alignment between GaAs and Ga (AsSb) is of type II with a conduction band offset of approximately 40 meV. © 2007 American Institute of Physics.
• Faccio, D., Averchi, A., Couairon, A., Kolesik, M., Moloney, J. V., Dubietis, A., Tamosauskas, G., Polesana, P., Piskarskas, A., & Trapani, P. D. (2007). Spatio-temporal reshaping and X Wave dynamics in optical filaments. Optics Express, 15(20), 13077-13095.
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  PMID: 19550576;Abstract: We investigate ultrashort laser pulse filamentation within the framework of spontaneous X Wave formation. After a brief overview of the filamentation process we study the case of an intense filament co-propagating with a weaker seed pulse. The filament is shown to induce strong Cross-Phase-Modulation (XPM) effects on the weak seed pulse: driven by the pump, the seed pulse undergoes pulse splitting with the daughter pulses slaved to their pump counterparts. They undergo strong spatio-temporal reshaping and are transformed into X Waves traveling at the same group velocities as the pump split-off pulses. In the presence of a gain mechanism such as Four-Wave-Mixing or Stimulated Raman Scattering, energy is then transferred from the pump filament leading to amplification of the seed X Wave and formation of a temporally compressed intensity peak. © 2007 Optical Society of America.
• Faccio, D., Averchi, A., Couairon, A., Kolesik, M., Moloney, J., Dubietis, A., Tamosauskas, G., Polesana, P., Piskarskas, A., & Di Trapani, P. (2007). Spatio-temporal reshaping and X Wave dynamics in optical filaments.. Optics express, 15(20), 13077--13095.
• Faccio, D., Averchi, A., Couairon, A., Kolesik, M., Moloney, J., Dubietis, A., Tamosauskas, G., Polesana, P., Piskarskas, A., & Di Trapani, P. (2007). X wave generation by Cross-Phase-Modulation induced spatio-temporal reshaping and amplification within optical filaments.. Opt. Expr.
• Fan, L., Fallahi, M., Hader, J., Zakharian, A. R., Moloney, J. V., Stolz, W., Koch, S. W., Bedford, R., & Murray, J. T. (2007). Linearly polarized dual-wavelength vertical-external-cavity surface-emitting laser. Applied Physics Letters, 90(18).
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  Abstract: The authors demonstrate the multiwatt linearly polarized dual-wavelength operation in an optically pumped vertical-external-cavity surface-emitting laser by means of an intracavity tilted Fabry-Perot etalon and a Brewster window. The sum frequency generation from the lithium triborate crystal pumped by this laser confirms that these two wavelengths oscillate simultaneously. Over 30 dB side-mode suppression can be achieved at dual wavelengths with a spectral spacing of 2.1 nm. The output power is slightly reduced by the intracavity Fabry-Perot etalon and Brewster window. © 2007 American Institute of Physics.
• Fan, L., Fallahi, M., Hader, J., Zakharian, A. R., Moloney, J. V., Stolz, W., Koch, S. W., Bedford, R., & Murray, J. T. (2007). Linearly polarized dual-wavelength vertical-external-cavity surface-emitting laser. Applied physics letters, 90(18), 181124.
• Fan, L., Fallahi, M., Zakharian, A. R., Hader, J., Moloney, J. V., Bedford, R., Murray, J. T., Stolz, W., & Koch, S. W. (2007). Extended tunability in a two-chip VECSEL. IEEE Photonics Technology Letters, 19(8), 544-546.
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  Abstract: We demonstrate a widely tunable vertical-external-cavity surface-emitting laser (VECSEL) with a W-shaped cavity, in which two VECSEL chips serve as fold mirrors and a birefringent filter is inserted at Brewster's angle. These two chips provide much higher modal gain and broader bandwidth of the gain than a single chip does, enhancing the VECSEL tuning range and reducing the variation of tunable output power with the tuned wavelength. This two-chip VECSEL configuration makes it possible to shape the modal gain spectra of the laser or to manipulate the tuning curve of the laser by two different chips with certain gain peak detuning (offset). Multiwatts high-brightness linearly polarized output with a tuning range of 33 nm is demonstrated in such a two-chip VECSEL. © 2007 IEEE.
• Fan, L., Fallahi, M., Zakharian, A. R., Hader, J., Moloney, J. V., Bedford, R., Murray, J. T., Stolz, W., & Koch, S. W. (2007). Extended tunability in a two-chip VECSEL. Photonics Technology Letters, IEEE, 19(8), 544--546.
• Fan, L., Hessenius, C., Fallahi, M., Hader, J., Hongbo, L. i., Moloney, J. V., Stolz, W., Koch, S. W., Murray, J. T., & Bedford, R. (2007). Highly strained InGaAsGaAs multiwatt vertical-external-cavity surface-emitting laser emitting around 1170 nm. Applied Physics Letters, 91(13).
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  Abstract: We develop and demonstrate a multiwatt highly strained InGaAsGaAs vertical-external-cavity surface-emitting laser with a free lasing wavelength of around 1170 nm. This laser can be tuned from ∼1147 to∼1197 nm. This low-cost compact wavelength agile laser can potentially provide high-power coherent light in a wide yellow-orange band by the intracavity frequency doubling. © 2007 American Institute of Physics.
• Fan, L., Hessenius, C., Fallahi, M., Hader, J., Li, H., Moloney, J. V., Stolz, W., Koch, S. W., Murray, J. T., & Bedford, R. (2007). Highly strained InGaAs/GaAs multiwatt vertical-external-cavity surface-emitting laser emitting around 1170 nm. Applied Physics Letters, 91(13), 1114.
• Gundu, K. M., Kolesik, M., & Moloney, J. V. (2007). Mode shaping in multicore fibers. Optics Letters, 32(7), 763-765.
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  PMID: 17339928;Abstract: We propose a novel multicore fiber design strategy for obtaining a fiat in-phase supermode that optimizes utilization of the active medium inversion in the multiple cores. The spatially flat supermode is achieved by engineering the fiber so that the total mutual coupling between neighboring active cores is equal. Different designs suitable for different fabrication processes, such as stack-and-draw and drilling, are proposed. An important improvement over previous methods is the design simplicity and better tolerance to perturbations. © 2007 Optical Society of America.
• Gundu, K. M., Kolesik, M., & Moloney, J. V. (2007). Mode shaping in multicore fibers. Optics letters, 32(7), 763--765.
• Hader, J., Moloney, J. V., & Koch, S. W. (2007). Erratum: "Influence of internal fields on gain and spontaneous emission in InGaN quantum wells" (Applied Physics Letters (2006) 89 (171120)). Applied Physics Letters, 90(25).
• Hader, J., Moloney, J. V., Thranhardt, A., Koch, S. W., & Piprek, J. (2007). Interband transitions in InGaN quantum wells. Nitride semiconductor devices.
• Hader, J., Moloney, J., & Koch, S. (2007). Erratum:“Influence of internal fields on gain and spontaneous emission in InGaN quantum wells”[Appl. Phys. Lett. 89, 171120 (2006)]. Applied Physics Letters, 90(25), 259901.
• Hongbo, L. i., Mafi, A., Schülzgen, A., Li, L. i., Temyanko, V. L., Peyghambarian, N., & Moloney, J. V. (2007). Analysis and design of photonic crystal fibers based on an improved effective-index method. Journal of Lightwave Technology, 25(5), 1224-1230.
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  Abstract: The modal characteristics of photonic crystal fibers (PCFs), with guiding cores consisting of one or seven missing airholes, are investigated with the finite element method and compared to those of step-index fibers (SIFs). To extend the applicability of the classical SIF theories to PCFs, the effective refractive index of photonic crystal cladding and the effective core radius of a PCF are studied systematically, based on simple physically consistent concepts. With the new effective cladding index and core radius of PCFs, the classical definition of the V parameter for SIFs is extended to PCFs, and a highly efficient approach based on the effective-index method is developed for the design of PCFs. The new design approach has been successfully employed to analyze the modal properties of PCF lasers with depressed-index cores and further tested by using it to effectively estimate the number of guided modes for PCFs with large cores. © 2007 IEEE.
• Hoyer, W., Kira, M., Koch, S. W., Hader, J., & Moloney, J. V. (2007). Coulomb effects on quantum-well luminescence spectra and radiative recombination times. JOSA B, 24(6), 1344--1353.
• Hoyer, W., Kira, M., Koch, S. W., Hader, J., & Moloney, J. V. (2007). Coulomb effects on quantum-well luminescence spectra and radiative recombination times. Journal of the Optical Society of America B: Optical Physics, 24(6), 1344-1353.
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  Abstract: A microscopic theory based on Bloch electrons and holes in a two-band approximation is applied in order to compute absorption and luminescence spectra for GaAs-type quantum wells at room temperature. Special focus is set to investigate the effect of the Coulomb interaction on the linewidth of the luminescence spectra and on the radiative recombination rates. © 2007 Optical Society of America.
• Hoyer, W., Kira, M., Koch, S., Moloney, J., & Wright, E. (2007). Light--matter interaction in finite-size plasma systems. physica status solidi (b), 244(10), 3540--3557.
• Kolesik, M., & Moloney, J. V. (2007). Time-domain vertical-external-cavity semiconductor laser simulation. IEEE Journal of Quantum Electronics, 43(7), 588-596.
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  Abstract: A time-domain simulator for Vertical External Cavity Semiconductor Lasers (VECSEL) is described in detail. The core of the model employs a digital filter method to model the optical properties of the active mirror over a wide range of frequencies, temperatures, and carrier densities. The method is also applicable without modifications to the time-domain simulation of semiconductor saturable mirrors (SESAM). As an illustration, ultrashort pulse generation is simulated in two kinds of devices: in a synchronously pumped VECSEL and in a laser passively mode-locked by SESAM. © 2007 IEEE.
• Kolesik, M., & Moloney, J. V. (2007). Time-domain vertical-external-cavity semiconductor laser simulation. Quantum Electronics, IEEE Journal of, 43(7), 588--596.
• Kolesik, M., Roskey, D. E., & Moloney, J. V. (2007). Conditional femtosecond pulse collapse for white-light and plasma delivery to a controlled distance. Optics Letters, 32(18), 2753-2755.
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  PMID: 17873958;Abstract: Collisions between ultrashort pulses with different wavelengths are studied numerically. The relative delay, wavelength difference, focusing geometry, and chirp are used to accurately control the distance at which pulses undergo conditional collapse and generate plasma and white light. A wide supercontinuum spectrum is achievable even with pulses that by themselves do not have sufficient power for filament formation. © 2007 Optical Society of America.
• Kolesik, M., Roskey, D., & Moloney, J. (2007). Conditional femtosecond pulse collapse for white-light and plasma delivery to a controlled distance. Optics letters, 32(18), 2753--2755.
• Kolesik, M., Wright, E., & Moloney, J. (2007). Supercontinuum and third-harmonic generation accompanying optical filamentation as first-order scattering processes. Optics letters, 32(19), 2816--2818.
• Lange, C., Chatterjee, S., Schlichenmaier, C., Thranhardt, A., Koch, S., Ruhle, W., Hader, J., Moloney, J., Khitrova, G., & Gibbs, H. (2007). Transient gain spectroscopy of (GaIn) As quantum wells: Experiment and microscopic analysis. Applied physics letters, 90(25), 251102--251102.
• Lee, K. S., Kim, C. S., Kim, R. K., Patterson, G., Kolesik, M., Moloney, J. V., & Peyghambarian, N. (2007). Dual-wavelength external cavity laser with a sampled grating formed in a silica PLC waveguide for terahertz beat signal generation. Applied Physics B: Lasers and Optics, 87(2), 293-296.
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  Abstract: We propose and demonstrate a dual-wavelength external cavity laser (ECL). In our design, a Fabry-Pérot laser diode (FP-LD) is hybrid-integrated with a sampled Bragg grating written in a silica planar lightwave circuit (PLC). The grating selects two laser wavelengths that share the same laser cavity. The dual-wavelength oscillation with a side mode suppression ratio >32 dB has been demonstrated experimentally. Experimental results indicate that the hybrid-integrated dual-wavelength ECL exhibits strong dual-wavelength emission corresponding to beat frequency of 1 THz. Simulations of this system also indicate good mutual coherence of the two modes and stability of the 1 THz beat signal. © Springer-Verlag 2007.
• Lee, K., Kim, C., Kim, R., Patterson, G., Kolesik, M., Moloney, J., & Peyghambarian, N. (2007). Dual-wavelength external cavity laser with a sampled grating formed in a silica PLC waveguide for terahertz beat signal generation. Applied Physics B, 87(2), 293--296.
• Li, H., Brio, M., Li, L., Sch\"ulzgen, A., Peyghambarian, N., & Moloney, J. V. (2007). Multimode interference in circular step-index fibers studied with the mode expansion approach. JOSA B, 24(10), 2707--2720.
• Li, H., Mafi, A., Sch\"ulzgen, A., Li, L., Temyanko, V. L., Peyghambarian, N., & Moloney, J. V. (2007). Analysis and design of photonic crystal fibers based on an improved effective-index method. Journal of lightwave technology, 25(5), 1224--1230.
• Li, L., Sch\"ulzgen, A., Li, H., Temyanko, V., Moloney, J., & Peyghambarian, N. (2007). Phase-locked multicore all-fiber lasers: modeling and experimental investigation. JOSA B, 24(8), 1721--1728.
• Li, L., Schülzgen, A., Li, H., Temyanko, V. L., Moloney, J. V., & Peyghambarian, N. (2007). Phase-locked multicore all-fiber lasers: Modeling and experimental investigation. Journal of the Optical Society of America B: Optical Physics, 24(8), 1721-1728.
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  Abstract: A systematic study on a compact, novel phase-locked multicore fiber laser device that is based on a truly all-fiber approach is presented. Supermode selection inside this monolithic fiber device is numerically analyzed, and multicore fiber lasers operating explicitly at the in-phase supermode are experimentally demonstrated. © 2007 Optical Society of America.
• Mansuripur, M., Zakharian, A. R., & Moloney, J. V. (2007). Surface plasmon polaritons on metallic surfaces. Optics and Photonics News, 18(4), 44--49.
• Mansuripur, M., Zakharian, A. R., & Moloney, J. V. (2007). Surface plasmon polaritons on metallic surfaces. Optics and Photonics News, 18(4), 44-49.
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  Abstract: Numerical simulations are used to verify the detailed structure of long range surface plasmon polaritons (SPP). The behavior of the electromagnetic eigenmodes confined to flat metallo-dielectric interfaces are determined with the help of Maxwells equation. Numerical computation based on finite difference time domain (FDTD) method are uses to determine of the modes to show the excitation of SPP in certain practical setting. Prism-coupling scheme can be used to excite SPPs on the flat surface of a metal slab. The odd and even waves that propagate along the surface of metallic slabs are examples of such long-range SPP. FDTD simulations provides a physical picture of field distributions and energy flow patterns in realistic systems that are generally inaccessible to exact mathematical analysis.
• Martinez, A., Li, Y., Lester, L. F., Gray, A. L., Lange, C., Chatterjee, S., Schlichenmaier, C., Thr\"anhardt, A., Koch, S., R\"uhle, W., & others, . (2007). LASERS, OPTICS, AND OPTOELECTRONICS. Appl. Phys. Lett, 90(25), 253101.
• Moloney, J. (2007). Software enables optimized epi structure in a single wafer growth. Laser Focus World, 43(7), 59-63.
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  Abstract: The Nonlinear Control Strategies of Tucson has won a Phase II STTR award from the U.S. Air Force to provide an enabling commercial software in optimizing epi structure in a single wafer growth. The practice in semiconductor materials growth has typically involved an estimation of the absorption-band edge via simple band-structure calculations followed by series of growth, packaging, and regrowth cycles. This problem has been addressed by demonstrating the ability to predict a semiconductor- laser input-output (L-I) characteristic based on fundamental principles without using adjustable fit parameters problem. The spectral lineshape at low external light illumination intensities yields photoluminescence (PL) spectra that provide invaluable feedback to the semiconductor-wafer grower on growth accuracy and quality. The predicted laser input-output characteristics were computed prior to the experimental measurement when a slight temperature elevation in the active region was allowed for.
• Moloney, J. V. (2007). Predictive semiconductor laser design free of fit parameters. Spie Newsroom. doi:10.1117/2.1200702.0536
• Moloney, J. V., & Kolesik, M. (2007). Full vectorial, intense ultrashort pulse propagators: Derivation and applications. Springer Series in Chemical Physics, 85, 253-280.
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  Abstract: Rapid progress in recent years in the development of high power ultra-short pulse laser systems has opened up a whole new vista of applications and computational challenges. New experimental developments in the field of extreme nonlinear optics will require more rigorous electromagnetic propagation models beyond those existing in the current literature. In this chapter, we derive a 3D time domain unidirectional vector Maxwell propagator that resolves the underlying optical carrier wave while allowing propagation over macroscopic many-meter distances. Our model allows for extreme focusing conditions down to the order of the wavelength in the material. A novel aspect of our approach is that the pulse propagator is designed to faithfully capture the light-material interaction over the broad spectral landscape of relevance to the interaction. Moreover the model provides a seamless and physically self-consistent means of deriving the many ultra-short pulse propagation equations presented in the literature. Amongst current applications that are most challenging from a computational point of view are those involving critical self-focusing with concomitant explosive growth in the generated light spectrum. Specific application areas chosen for illustration include multiple filament formation during propagation of ultra-intense femtosecond laser pulses in air and nonlinear self-trapping in condensed media. These examples exhibit rather different aspects of intense femtosecond pulse propagation and demonstrate the robustness and flexibility of our recently formulated unidirectional Maxwell propagator. A clear message to emerge from our study is the inadequacy of spectrally local light-material interaction models when nonlinear coupling exists over many hundreds of nanometer frequency bandwidths. More sophisticated, computationally feasible, models of nonlinear dispersion are needed. © 2007 Springer-Verlag.
• Moloney, J. V., Hader, J., & Koch, S. W. (2007). Quantum design of semiconductor active materials: Laser and amplifier applications. Laser and Photonics Reviews, 1(1), 24-43.
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  Abstract: We present an overview of a novel first-principles quantum approach to designing and optimizing semiconductor quantum-well material systems for target wavelengths. Using these microscopic inputs as basic building blocks we predict the light-current (LI) characteristic for a low power InGaPAs ridge laser without having to use adjustable fit parameters. Finally we employ these microscopic inputs to develop sophisticated simulation capabilities for designing and optimizing end packaged high power laser structures. As an explicit example of the latter, we consider the design of a vertical external cavity semiconductor laser (VECSEL). A graph is presented. Experimental (circles and squares) and theoretical (solid lines) photoluminescence (green/blue) and modal gain (black/red) for a 5-nm wide InGaAs quantum well sandwiched between GaAs barriers. © 2007 by Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
• Moloney, J. V., Hader, J., & Koch, S. W. (2007). Quantum design of semiconductor active materials: laser and amplifier applications. Laser \& Photonics Reviews, 1(1), 24--43.
• Pantha, B., Dahal, R., Nakarmi, M., Nepal, N., Li, J., Lin, J., Jiang, H., Paduano, Q., Weyburne, D., Diehl, W., & others, . (2007). LASERS, OPTICS, AND OPTOELECTRONICS. Appl. Phys. Lett, 90(24), 243104.
• Peleg, A., & Moloney, J. V. (2007). Scintillation index for N Gaussian laser beams with different wavelengths in weak atmospheric turbulence. Proceedings of SPIE, 6457. doi:10.1117/12.711187
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  We study the scintillation index of N partially overlapping lowest order Gaussian laser beams with different wavelengths in weak atmospheric turbulence. Assuming a Von Karman turbulence spectrum and slow detector response and using the Rytov approximation we calculate the longitudinal and radial components of the scintillation index for typical free-space laser communication setups. We find the initial beam separation that minimizes the longitudinal scintillation and corresponds to the optimal beam configuration. Further reduction of the longitudinal scintillation is obtained by optimizing with respect to both initial beam separation and initial spot size. The longitudinal scintillation of the optimal N -beam configurations is inversely proportional to N , resulting in a 92% reduction for a 9-beam system compared with the single beam value. The existence of the minimum of longitudinal scintillation is not very sensitive to the form of the turbulence spectrum. Moreover, the radial scintillation values for the optimal N-beam configurations are found to be significantly smaller than the corresponding single beam values, and this reduction effect also grows with increasing N .
• Peleg, A., & Moloney, J. V. (2007). Scintillation reduction by use of multiple Gaussian laser beams with different wavelengths. IEEE Photonics Technology Letters, 19(12), 883-885.
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  Abstract: We study the scintillation index of N partially overlapping collimated lowest order Gaussian laser beams with different wavelengths in weak atmospheric turbulence. Using the Rytov approximation, we calculate the initial beam separation that minimizes the longitudinal scintillation. Further reduction of the longitudinal scintillation is obtained by optimizing with respect to both beam separation and spot size. The longitudinal scintillation of the optimal N-beam configurations is inversely proportional to N, resulting in a 92% reduction for a nine-beam system compared with the single beam value. The radial scintillation values for the optimal N-beam configurations are significantly smaller than the corresponding single beam values. © 2007 IEEE.
• Peleg, A., & Moloney, J. V. (2007). Scintillation reduction by use of multiple Gaussian laser beams with different wavelengths. Photonics Technology Letters, IEEE, 19(12), 883--885.
• Peyghambarian, N., Moloney, J. V., Roussev, R. V., Polynkin, P., Peyghambarian, N., & Fejer, M. M. (2007). Laser transmitter at 518 nm for optical undersea communications using efficient nonlinear conversion of a picosecond fiber-laser system at 1.56μm. Frontiers in Optics. doi:10.1364/fio.2007.fwb6
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  Viable laser transmitter for emerging optical undersea communications is reported. The high data-rate, picosecond fiber-laser system at 1.56µm is frequency-tripled into transparency window of seawater in cascade of two PPLN crystals operated at room temperature.
• Polynkin, P., Peleg, A., Klein, L., Rhoadarmer, T., & Moloney, J. (2007). Optimized multiemitter beams for free-space optical communications through turbulent atmosphere. Optics Letters, 32(8), 885-887.
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  PMID: 17375142;Abstract: Using laser beams with less than perfect spatial coherence is an effective way of reducing scintillations in free-space optical communication links. We report a proof-of-principle experiment that quantifies this concept for a particular type of a partially coherent beam. In our scaled model of a free-space optical communication link, the beam is composed of several partially overlapping fundamental Gaussian beams that are mutually incoherent. The turbulent atmosphere is simulated by a random phase screen imprinted with Kolmogorov turbulence. Our experiments show that for both weak-to-intermediate and strong turbulence an optimum separation between the constituent beams exists such that the scintillation index of the optical signal at the detector is minimized. At the minimum, the scintillation reduction factor compared with the case of a single Gaussian beam is substantial, and it is found to grow with the number of constituent beams. For weak-to-intermediate turbulence, our experimental results are in reasonable agreement with calculations based on the Rytov approximation. © 2007 Optical Society of America.
• Polynkin, P., Peleg, A., Klein, L., Rhoadarmer, T., & Moloney, J. (2007). Optimized multiemitter beams for free-space optical communications through turbulent atmosphere. Optics letters, 32(8), 885--887.
• Polynkin, P., Roussev, R., Fejer, M. M., Peyghambarian, N., & Moloney, J. (2007). Laser transmitter for undersea communications using third-harmonic generation of fiber-laser system at 1.5 μm. IEEE Photonics Technology Letters, 19(17), 1328-1330.
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  Abstract: We report a viable laser transmitter for free-space undersea communications. An all-fiber, picosecond, Watt-level master-oscillator-power-amplifier (MOPA) system at 1.5 μm based on rapid amplification of mode-locked pulses in heavily Er:Yb codoped phosphate fiber is combined with fiber pigtailed lithium niobate intensity modulator (pulse picker), to construct a fully integrated eye-safe transmitter operating at 65-Mb/s data rate, that can be used in intermediate-range (few kilometers) atmospheric communication links. For undersea use, the output of the MOPA system is frequency-tripled into the blue-green transparency window of ocean water. The wavelength conversion occurs in a simple single-pass setup utilizing a sequence of two periodically poled lithium niobate crystals, both of which are operated at room temperature. The conversion efficiency from fundamental to third harmonic reached 14% and resulted in generation of 140 mW of average power at 518 nm. The conversion efficiency can be straightforwardly increased threefold using properly antireflection-coated optics in the free-space part of the setup, and the data rate can be scaled up into the gigabit-per-second range by using a faster mode-locked oscillator in the MOPA system. © 2007 IEEE.
• Polynkin, P., Roussev, R., Fejer, M., Peyghambarian, N., & Moloney, J. (2007). Laser Transmitter for Undersea Communications Using Third-Harmonic Generation of Fiber-Laser System at 1.5 $\mu$ m. Photonics Technology Letters, IEEE, 19(17), 1328--1330.
• Polynkin, P., Temyanko, V., Moloney, J., & Peyghambarian, N. (2007). Dramatic change of guiding properties in heavily Yb-doped, soft-glass active fibers caused by optical pumping. Applied Physics Letters, 90(24).
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  Abstract: The authors report experimentally observed qualitative changes of the waveguiding properties in ytterbium-doped fibers with high concentration of doping when the fibers are optically pumped with light at the 975 nm wavelength. They found that when concentration of Yb2 O3 in a single-mode fiber exceeds ∼10 wt. % and the pump power is gradually increased, the fiber first looses index-induced guidance, and then regains guidance as the population inversion in Yb+3 ions becomes sufficient for gain guiding. The associated variation of the mode-field diameter is a practically important effect that will complicate design and operation of fiber lasers and amplifiers based on highly Yb-doped glass. © 2007 American Institute of Physics.
• Polynkin, P., Temyanko, V., Moloney, J., & Peyghambarian, N. (2007). Dramatic change of guiding properties in heavily Yb-doped, soft-glass active fibers caused by optical pumping. Applied physics letters, 90(24), 241106.
• Roskey, D., Kolesik, M., Moloney, J., & Wright, E. (2007). Self-action and regularized self-guiding of pulsed bessel-like beams in air. Optics express, 15(16), 9893--9907.
• Roskey, D., Kolesik, M., Moloney, J., & Wright, E. (2007). The role of linear power partitioning in beam filamentation. Applied Physics B, 86(2), 249--258.
• Zakharian, A. R., Moloney, J. V., & Mansuripur, M. (2007). Surface plasmon polaritons on metallic surfaces. IEEE Transactions on Magnetics, 43(2), 845-850.
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  Abstract: A theoretical study of surface plasmon polaritons on flat metallic surfaces and interfaces is undertaken to clarify the nature of these electromagnetic waves, conditions under which they are launched, and the restrictions imposed by Maxwell's equations that ultimately determine the strength of the excited plasmons. Finite difference time domain (FDTD) computer simulations are used to provide a clear picture of the electromagnetic field distribution and the energy flow profile in each of the cases studied. © 2007 IEEE.
• Zakharian, A. R., Moloney, J. V., & Mansuripur, M. (2007). Surface plasmon polaritons on metallic surfaces. Optics Express, 15(1), 183-197.
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  PMID: 19532234;Abstract: A unified theoretical study of surface plasmon polaritons on flat metallic surfaces and interfaces is undertaken to clarify the nature of these electromagnetic waves, conditions under which they are launched, and the restrictions imposed by Maxwell's equations that ultimately determine the strength of the excited plasmons. Finite Difference Time Domain computer simulations are used to provide a clear picture of the electromagnetic field distribution and the energy flow profile in a specific situation. The examined case involves the launching of plasmonic waves on the entrance facet of a metallic host perforated by a subwavelength slit, and the (simultaneous) excitation of the slit's guided mode. © 2007 Optical Society of America.
• Zakharian, A. R., Moloney, J. V., & Mansuripur, M. (2007). Surface plasmon polaritons on metallic surfaces. Optics express, 15(1), 183--197.
• Zhu, X., Sch\vRlzgen, A., Li, L., Li, H., Temyanko, V., Moloney, J., & Peyghambarian, N. (2007). Birefringent in-phase supermode operation of a multicore microstructured fiber laser. Optics express, 15(16), 10340--10345.
• Zhu, X., Schülzgen, A., Li, L., Li, H., Temyanko, V. L., Moloney, J. V., & Peyghambarian, N. (2007). Birefringent in-phase supermode operation of a multicore microstructured fiber laser. Optics Express, 15(16), 10340-10345.
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  PMID: 19547384;Abstract: We report the first observation of birefringent in-phase supermode operation of a phase-locked multicore fiber laser. The in-phase mode operation of our 12-core rectangular-array microstructured fiber laser was confirmed by the near-field distribution, the far-field diffraction pattern, and the optical spectrum. The birefringence of the in-phase mode in propagation constant Δγ was measured as ∼ 4 × 10-6 1/μm. The break of the polarization degeneracy indicates the possibility of single polarization operation of phase-locked multicore fiber lasers and amplifiers. © 2007 Optical Society of America.
• F\"orstner, J., Knorr, A., & Moloney, J. (2006). Interplay of electron-phonon and Coulomb interaction in semiconductor quantum dots. physica status solidi (c), 3(7), 2389--2392.
• Fan, L., Fallahi, M., Hader, J., Zakharian, A. R., Moloney, J. V., Murray, J. T., Bedford, R., Stolz, W., & Koch, S. W. (2006). Multichip vertical-external-cavity surface-emitting lasers: A coherent power scaling scheme. Optics Letters, 31(24), 3612-3614.
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  PMID: 17130920;Abstract: We propose an efficient coherent power scaling scheme, the multichip vertical-external-cavity surface-emitting laser (VECSEL), in which the waste heat generated in the active region is distributed on multi-VECSEL chips such that the pump level at the thermal rollover is significantly increased. The advantages of this laser are discussed, and the development and demonstration of a two-chip VECSEL operating around 970 nm with over 19 W of output power is presented. © 2006 Optical Society of America.
• Fan, L., Fallahi, M., Hader, J., Zakharian, A. R., Moloney, J. V., Murray, J. T., Bedford, R., Stolz, W., & Koch, S. W. (2006). Multichip vertical-external-cavity surface-emitting lasers: a coherent power scaling scheme. Optics letters, 31(24), 3612--3614.
• Fan, L., Fallahi, M., Murray, J. T., Bedford, R., Kaneda, Y., Zakharian, A. R., Hader, J., Moloney, J. V., Stolz, W., & Koch, S. W. (2006). Tunable high-power high-brightness linearly polarized vertical-external-cavity surface-emitting lasers. Applied Physics Letters, 88(2), 1-3.
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  Abstract: We report on the development and the demonstration of tunable high-power high-brightness linearly polarized vertical-external-cavity surface-emitting lasers (VECSELs). A V-shaped cavity, in which the antireflection-coated VECSEL chip (active mirror) is located at the fold, and a birefringent filter are employed to achieve a large wavelength tuning range. Multiwatt cw linearly polarized TEM00 output with a 20 nm tuning range and narrow linewidth is demonstrated at room temperature. © 2006 American Institute of Physics.
• Fan, L., Fallahi, M., Murray, J. T., Bedford, R., Kaneda, Y., Zakharian, A. R., Hader, J., Moloney, J. V., Stolz, W., & Koch, S. W. (2006). Tunable high-power high-brightness linearly polarized vertical-external-cavity surface-emitting lasers. Applied physics letters, 88(2), 021105.
• Fan, L., Hsu, T., Fallahi, M., Murray, J. T., Bedford, R., Kaneda, Y., Hader, J., Zakharian, A. R., Moloney, J. V., Koch, S. W., & Stolz, W. (2006). Tunable watt-level blue-green vertical-external-cavity surface-emitting lasers by intracavity frequency doubling. Applied Physics Letters, 88(25).
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  Abstract: We report, on the development and the demonstration of a tunable, watt-level, blue-green, linearly polarized vertical-external-cavity surface-emitting lasers operating around 488 nm by intracavity second-harmonic generation. By using lithium triborate crystal, we have achieved over 1.3 W continuous wave blue-green power at 488 nm with a 5 nm tunability. © 2006 American Institute of Physics.
• Fan, L., Hsu, T., Fallahi, M., Murray, J. T., Bedford, R., Kaneda, Y., Hader, J., Zakharian, A. R., Moloney, J. V., Koch, S. W., & others, . (2006). Tunable watt-level blue-green vertical-external-cavity surface-emitting lasers by intracavity frequency doubling. Applied physics letters, 88(25), 1117.
• Förstner, J., Knorr, A., & Moloney, J. V. (2006). Interplay of electron-phonon and Coulomb interaction in semiconductor quantum dots. Physica Status Solidi (C) Current Topics in Solid State Physics, 3(7), 2389-2392.
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  Abstract: We theoretically study the biexciton-phonon interaction in strongly confined semiconductor quantum dots. For spectrally narrow single-pulse excitation generation of biexcitonic occupations is only possible via a two-photon cascade, which exhibits renormalized Rabi oscillations and spectrally compressed phonon-sidebands. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA.
• Gundu, K. M., Kolesik, M., Moloney, J. V., & Lee, K. S. (2006). Ultra-flattened-dispersion selectively liquid-filled photonic crystal fibers. Optics Express, 14(15), 6870-6878.
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  PMID: 19516870;Abstract: We propose a method to control the chromatic dispersion properties of photonic crystal fibers using the selective hole filling technique. The method is based on a single hole-size fiber geometry, and uses an appropriate index-matching liquid to modify the effective size of the filled holes. The dependence of dispersion properties of the fiber on the design parameters such as the refractive index of the liquid, lattice constant and hole diameter are studied numerically. It is shown that very small dispersion values between 0±0.5ps/nm-km can be achieved over a bandwidth of 430-510nm in the communication wavelength region of 1300-1900nm. Three such designs are proposed with air hole diameters in the range 1.5-2.0μm. © 2006 Optical Society of America.
• Gundu, K. M., Kolesik, M., Moloney, J. V., & Lee, K. S. (2006). Ultra-flattened-dispersion selectively liquid-filled photonic crystal fibers. Optics express, 14(15), 6870--6878.
• Hader, J., Moloney, J. V., & Koch, S. W. (2006). Influence of internal fields on gain and spontaneous emission in InGaN quantum wells. Applied Physics Letters, 89(17).
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  Abstract: Fully microscopic models are used to investigate the structural dependence of InGaNGaN quantum-well semiconductor-laser gain media. Due to the inherent piezoelectric fields, the amplitudes and spectral positions of gain and spontaneous emission strongly depend on the structural details. It is shown how quantitative experiment/theory comparisons can be used to determine the fields. As a general trend, it is found that the loss current due to spontaneous emission at threshold decreases with well width and indium composition. © 2006 American Institute of Physics.
• Hader, J., Moloney, J. V., Fallahi, M., Fan, L. i., & Koch, S. W. (2006). Closed-loop design of a semiconductor laser. Optics Letters, 31(22), 3300-3302.
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  PMID: 17072403;Abstract: We provide what we believe is the first closed-loop prediction of a semiconductor laser performance using fully microscopic many-body models for the spontaneous emission, gain, and carrier recombination losses due to Auger processes without having to resort to phenomenological adjustable fit parameters. © 2006 Optical Society of America.
• Hader, J., Moloney, J. V., Fallahi, M., Fan, L., & Koch, S. W. (2006). Closed-loop design of a semiconductor laser. Optics letters, 31(22), 3300--3302.
• Hader, J., Moloney, J., & Koch, S. (2006). Influence of internal fields on gain and spontaneous emission in InGaN quantum wells. Applied physics letters, 89(17), 171120--171120.
• Kaneda, Y., Fan, L., Hsu, T., Peyghambarian, N., Fallahi, M., Zakharian, A. R., Hader, J., Moloney, J. V., Stoltz, W., Koch, S., & others, . (2006). High brightness spectral beam combination of high-power vertical-external-cavity surface-emitting lasers. Photonics Technology Letters, IEEE, 18(17), 1795--1797.
• Kaneda, Y., Fan, L., Hsu, T., Peyghambarian, N., Fallahi, M., Zakharian, A. R., Hader, J., Moloney, J. V., Stoltz, W., Koch, S., Bedford, R., Sevian, A., & Glebov, L. (2006). High brightness spectral beam combination of high-power vertical-external-cavity surface-emitting lasers. IEEE Photonics Technology Letters, 18(17), 1795-1797.
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  Abstract: High brightness spectral beam combination of two high-power vertical-external-cavity surface-emitting laser (VECSEL) using volume Bragg grating in a photo-thermo-refractive (PTR) glass is demonstrated. High efficiency beam combination in excess of 90% is achieved, providing an efficient method for power scaling of diffraction limited beam. The beam quality of each starting lasers was 1.68 and 1.35, and that of combined beam was 1.9. Scaling opportunities based on the parameters of VECSELs and PTR Bragg gratings are discussed. © 2006 IEEE.
• Kano, P. O., Brio, M., Moloney, J. V., & others, . (2006). Numerical analysis of the ab initio computation of the effects of ionization on the nonlinear susceptibility coefficients of the hydrogen atom. Communications in Mathematical Sciences, 4(1), 53--80.
• Kolesik, M., Wright, E., Becker, A., & Moloney, J. (2006). Simulation of third-harmonic and supercontinuum generation for femtosecond pulses in air. Applied Physics B, 85(4), 531--538.
• Li, L., Sch\"ulzgen, A., Chen, S., Temyanko, V., Moloney, J., & Peyghambarian, N. (2006). Phase locking and in-phase supermode selection in monolithic multicore fiber lasers. Optics letters, 31(17), 2577--2579.
• Li, L., Sch\"ulzgen, A., Temyanko, V., Morrell, M., Sabet, S., Li, H., Moloney, J., & Peyghambarian, N. (2006). Ultracompact cladding-pumped 35-mm-short fiber laser with 4.7-W single-mode output power. Applied physics letters, 88(16), 1106.
• Li, L., Schülzgen, A., Chen, S., Temyanko, V. L., Moloney, J. V., & Peyghambarian, N. (2006). Phase locking and in-phase supermode selection in monolithic multicore fiber lasers. Optics Letters, 31(17), 2577-2579.
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  PMID: 16902624;Abstract: We report a compact multicore fiber laser that utilizes an all-fiber approach for phase locking and in-phase supermode selection. By splicing passive coreless fibers of controlled lengths to both ends of an active 19-core fiber, we demonstrate that the fundamental in-phase supermode can be selectively excited with a completely monolithic fiber device, instead of conventional free-space and bulk optics, to achieve phase-locked operation for a multiemitter laser device. © 2006 Optical Society of America.
• Li, L., Schülzgen, A., Temyanko, V. L., Morrell, M. M., Sabet, S., Li, H., Moloney, J. V., & Peyghambarian, N. (2006). Ultracompact cladding-pumped 35-mm -short fiber laser with 4.7-W single-mode output power. Applied Physics Letters, 88(16).
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  Abstract: We report on ultracompact cladding-pumped fiber lasers, fabricated from single-mode phosphate glass microstructured optical fibers, with several watts of cw output at 1.5 μm. A maximum cw output power of 4.7 W has been achieved from a fiber laser that is only 35 mm in length, corresponding to a yield of 1.34 Wcm of active microstructured fiber. © 2006 American Institute of Physics.
• Liu, T., Fallahi, M., Moloney, J. V., & Mansuripur, M. (2006). Fabrication of two-dimensional photonic crystals with embedded defects using blue-laser-writer and holography. Microelectronic Engineering, 83(4-9 SPEC. ISS.), 1778-1781.
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  Abstract: We have demonstrated an approach of relatively rapid fabrication of two-dimensional photonic crystals with embedded defects by combining a custom-built blue-laser-writer and the technique of optical holography. The blue-laser-writer is used to define various defect patterns first, and then the optical holography is used to create two-dimensional photonic crystals on the samples with the pre-defined defects. A beam splitter was fabricated based on this new method and characterized. © 2005 Elsevier B.V. All rights reserved.
• Liu, T., Fallahi, M., Moloney, J. V., & Mansuripur, M. (2006). Fabrication of two-dimensional photonic crystals with embedded defects using blue-laser-writer and holography. Microelectronic engineering, 83(4), 1778--1781.
• Liu, T., Fallahi, M., Moloney, J. V., & Mansuripur, M. (2006). Fabrication of two-dimensional photonic crystals with embedded defects using blue-laser-writer and optical holography. IEEE Photonics Technology Letters, 18(9), 1100-1102.
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  Abstract: We have demonstrated an approach of relatively rapid fabrication of two-dimensional (2-D) photonic crystals (PCs) with embedded defects by combining a custom-built blue-laser-writer and the technique of optical holography. The blue-laser-writer is used to define various defect patterns first, and then the optical holography is used to create 2-D PCs on the samples with the predefined defects. A beam splitter was fabricated based on this new method and characterized. © 2006 IEEE.
• Liu, T., Fallahi, M., Moloney, J. V., & Mansuripur, M. (2006). Fabrication of two-dimensional photonic crystals with embedded defects using blue-laser-writer and optical holography. Photonics Technology Letters, IEEE, 18(9), 1100--1102.
• M\'ejean, G., Ackermann, R., Kasparian, J., Salmon, E., Yu, J., Wolf, J., Rethmeier, K., Kalkner, W., Rohwetter, P., Stelmaszczyk, K., & others, . (2006). LASERS, OPTICS, AND OPTOELECTRONICS. Appl. Phys. Lett, 88(2), 023101.
• Moloney, J. V., Förstner, J., & Knorr, A. (2006). Interplay of electron–phonon and Coulomb interaction in semiconductor quantum dots. physica status solidi c, 3(7), 2379-2379. doi:10.1002/pssc.200690010
• Panasenko, D., Polynkin, P., Polynkin, A., Moloney, J. V., Mansuripur, M., & Peyghambarian, N. (2006). Er-Yb femtosecond ring fiber oscillator with 1.1-W average power and GHz repetition rates. IEEE Photonics Technology Letters, 18(7), 853-855.
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  Abstract: We report an all-fiber passively mode-locked femtosecond laser oscillator based on the heavily doped Er-Yb phosphate-glass active fiber. Only 20 cm of the gain fiber is sufficient to produce as much as 1.1 W of average output power at 1.5 μm directly from the oscillator. The laser can be harmonically mode-locked at repetition rates ranging from 1.7 to 7.2 GHz by adjusting the polarization bias in the cavity. The pulsewidth varies from 300 to 570 fs at the lowest and the highest repetition rate, respectively, and the maximum peak pulse power exceeds 1 kW. © 2006 IEEE.
• Panasenko, D., Polynkin, P., Polynkin, A., Moloney, J. V., Mansuripur, M., & Peyghambarian, N. (2006). Er-Yb femtosecond ring fiber oscillator with 1.1-W average power and GHz repetition rates. Photonics Technology Letters, IEEE, 18(7), 853--855.
• Peleg, A., & Moloney, J. V. (2006). Scintillation index for two Gaussian laser beams with different wavelengths in weak atmospheric turbulence. JOSA A, 23(12), 3114--3122.
• Peleg, A., & Moloney, J. V. (2006). Scintillation index for two Gaussian laser beams with different wavelengths in weak atmospheric turbulence. Journal of the Optical Society of America A: Optics and Image Science, and Vision, 23(12), 3114-3122.
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  PMID: 17106466;Abstract: We study the propagation of the two lowest-order Gaussian laser beams with different wavelengths in weak atmospheric turbulence. Using the Rytov approximation and assuming a slow detector, we calculate the longitudinal and radial components of the scintillation index for a typical free-space laser communication setup. We find the optimal configuration of the two laser beams with respect to the longitudinal scintillation index. We show that the value of the longitudinal scintillation for the optimal two-beam configuration is smaller by more than 50% compared with the value for a single lowest-order Gaussian beam with the same total power. Furthermore, the radial scintillation for the optimal two-beam system is smaller by 35%-40% compared with the radial scintillation in the single-beam case. Further insight into the reduction of intensity fluctuations is gained by analyzing the self- and cross-intensity contributions to the scintillation index. © 2006 Optical Society of America.
• Polynkin, A., Polynkin, P., Panasenko, D., Mansuripur, M., Moloney, J., & Peyghambarian, N. (2006). Short-cavity, passively modelocked fibre laser oscillator at 1.5 $\mu$m with 550 MHz repetition rate and high average power. Electronics letters, 42(3), 157--159.
• Polynkin, A., Polynkin, P., Panasenko, D., Mansuripur, M., Moloney, J., & Peyghambarian, N. (2006). Short-cavity, passively modelocked fibre laser oscillator at 1.5 μm with 550 MHz repetition rate and high average power. Electronics Letters, 42(3), 41-42.
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  Abstract: A short-cavity fibre laser oscillator emitting 12 ps-long pulses at the fundamental cavity frequency of 550 MHz is reported. The simple, stable and ultra-compact laser cavity consists of a short active fibre section which is spliced to a narrowband fibre Bragg grating, and a butt-coupled semiconductor saturable absorber mirror. Only 8 cm of the heavily Er/Yb co-doped phosphate-glass active fibre is sufficient to produce as much as 775 mW of average output power at 1.5 μm directly from the oscillator.
• Polynkin, P., Polynkin, A., Panasenko, D., Peyghambarian, N., & Moloney, J. (2006). Generating ultrafast pulses by direct amplification in short, heavily doped phosphate-glass fiber. Optics and Photonics News, 17(12), 49-.
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  Abstract: A simple alternative, which utilizes direct amplification of ultrashort pulses in a short and heavily-doped active fiber made of soft phosphate glass, is presented. The amplification was so rapid that no significant pulse distortion occurred in either the temporal or spectral domain. Both oscillator and amplifier stages utilize short pieces of side-pumped phosphate fiber as gain elements. The core of the single-mode active fiber is heavily co-doped with Er and Yb ions. The short-pulse operation of the oscillator is initiated by the semiconductor saturable absorber mirror (SESAM), which serves as one of the reflectors in the standing-wave laser cavity. Further power up-scaling is possible by using a large-mode area fiber in the amplifier stage.
• Polynkin, P., Polynkin, A., Panasenko, D., Peyghambarian, N., & Moloney, J. V. (2006). All-fiber picosecond laser system at 1.5 m based on amplification in short and heavily doped phosphate-glass fiber. Photonics Technology Letters, IEEE, 18(21), 2194--2196.
• Polynkin, P., Polynkin, A., Panasenko, D., Peyghambarian, N., & Moloney, J. V. (2006). All-fiber picosecond laser system at 1.5 μm based on amplification in short and heavily doped phosphate-glass fiber. IEEE Photonics Technology Letters, 18(21), 2194-2196.
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  Abstract: Amplification of ultrashort pulses in doped fibers is limited by an onset of nonlinear effects in the fiber. At the 1.5-μm wavelength single-mode fibers typically have anomalous dispersion. The self-phase modulation combined with dispersion leads to instability of multinanojoule pulses in such fibers. Various techniques developed to amplify pulses beyond the nonlinearity limit typically rely on a delicate balance between dispersive and nonlinear effects in different parts of the laser system. We report a simple all-fiber alternative to these complex techniques that utilizes a rapid amplification of pulses in a short and heavily doped phosphate-glass active fiber. In our preliminary experiments, picosecond pulses at 1.5 μm generated by a passively mode-locked fiber oscillator at a repetition rate of 70 MHz are amplified in a 15-cm-long heavily Er-Yb codoped fiber amplifier to the average output power of 1.425 W. The pulse energy and peak power reach 20.4 nJ and 16.6 kW, respectively, while the pulse distortion is minimal in both temporal and spectral domains. Further power up-scaling is possible by using active phosphate fiber with a large mode area, in the amplifier stage. © 2006 IEEE.
• Polynkin, P., Polynkin, A., Panasenko, D., Peyghambarian, N., Mansuripur, M., & Moloney, J. (2006). All-fiber passively mode-locked laser oscillator at 1.5 $\mu$m with watts-level average output power and high repetition rate. Optics letters, 31(5), 592--594.
• Polynkin, P., Polynkin, A., Panasenko, D., Peyghambarian, N., Mansuripur, M., & Moloney, J. (2006). All-fiber passively mode-locked laser oscillator at 1.5 μm with watts-level average output power and high repetition rate. Optics Letters, 31(5), 592-594.
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  PMID: 16570408;Abstract: We report on a passively mode-locked all-fiber laser oscillator at 1.5 μm based on heavily doped phosphate-glass active fiber. An active fiber only 20 cm long is sufficient to produce as much as 2.4 W of average output power directly from the oscillator. The width of the mode-locked pulses varies from 8 ps at the lowest output power in the mode-locked state to 44 ps at the highest power. Our picosecond laser oscillator features a high repetition rate of 95 MHz and high peak pulse power of ∼540 W. The oscillator combines the convenience of all-fiber construction with power performance that was previously achievable only with mode-locked bulk-optic laser oscillators or more complex systems involving fiber amplifiers. © 2006 Optical Society of America.
• Reichelt, M., Koch, S., Krasavin, A., Moloney, J., Schwanecke, A., Stroucken, T., Wright, E., & Zheludev, N. (2006). Broken enantiomeric symmetry for electromagnetic waves interacting with planar chiral nanostructures. Applied Physics B, 84(1-2), 97--101.
• Sch\vRlzgen, A., Li, L., Temyanko, V., Suzuki, S., Moloney, J., & Peyghambarian, N. (2006). Single-frequency fiber oscillator with watt-level output power using photonic crystal phosphate glass fiber. Optics express, 14(16), 7087--7092.
• Schülzgen, A., Li, L., Temyanko, V. L., Suzuki, S., Moloney, J. V., & Peyghambarian, N. (2006). Single-frequency fiber oscillator with watt-level output power using photonic crystal phosphate glass fiber. Optics Express, 14(16), 7087-7092.
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  PMID: 19529079;Abstract: Utilizing phosphate glass fiber with photonic crystal cladding and highly doped, large area core a cladding-pumped, single-frequency fiber oscillator is demonstrated. The fiber oscillator contains only 3.8 cm of active fiber in a linear cavity and operates in the 1.5 micron region. Spectrally broad, multimode pump light from semiconductor laser diodes is converted into a single-mode, single-frequency light beam with an efficiency of about 12% and the oscillator output power reached 2.3 W. © 2006 Optical Society of America.
• Suzuki, S., Schulzgen, A., Sabet, S., Moloney, J., & Peyghambarian, N. (2006). Photosensitivity of Ge-doped phosphate glass to 244 nm irradiation. Applied physics letters, 89(17), 171913--171913.
• Suzuki, S., Schülzgen, A., Sabet, S., Moloney, J. V., & Peyghambarian, N. (2006). Photosensitivity of Ge-doped phosphate glass to 244 nm irradiation. Applied Physics Letters, 89(17).
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  Abstract: UV photosensitivity of Ge-doped phosphate glasses is examined by writing photoinduced gratings in bulk glass samples. Radiation-induced index changes up to ∼3.5× 10-5 were obtained by diffraction efficiency measurements of UV written gratings. In contrast to phosphate glasses without intentional doping, no significant photodarkening at visible wavelength was observed in Ge-doped phosphate glasses after UV exposure. The measured index changes demonstrate the potential of Ge-doped phosphate glasses for the fabrication of a fiber Bragg grating, a key component for phosphate-glass-based photonic devices. © 2006 American Institute of Physics.
• Thr\"anhardt, A., B\"uckers, C., Schlichenmaier, C., Kuznetsova, I., Koch, S., Hader, J., & Moloney, J. (2006). Microscopic simulation of semiconductor lasers at telecommunication wavelengths. Optical and quantum electronics, 38(12-14), 1005--1009.
• Thr\"anhardt, A., Koch, S., Hader, J., & Moloney, J. (2006). Carrier dynamics in quantum well lasers. Optical and quantum electronics, 38(4-6), 361--368.
• Thr\"anhardt, A., Meier, T., Reichelt, M., Schlichenmaier, C., Pasenow, B., Kuznetsova, I., Becker, S., Stroucken, T., Hader, J., Zakharian, A., & others, . (2006). Microscopic modeling of the optical properties of semiconductor nanostructures. Journal of non-crystalline solids, 352(23), 2480--2483.
• Thränhardt, A., Bückers, C., Schlichenmaier, C., Kuznetsova, I., Koch, S. W., Hader, J., & Moloney, J. V. (2006). Microscopic simulation of semiconductor lasers at telecommunication wavelengths. Optical and Quantum Electronics, 38(12-14), 1005-1009.
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  Abstract: We consider two GaAs-based laser materials emitting at telecommunication wavelengths, namely the dilute nitride (GaIn)(NAs) as well as Ga(AsSb), and model their optical properties by including scattering and dephasing on a microscopic basis. The theory shows an excellent agreement with experiment without the inclusion of fit parameters such as phenomenological scattering times. By careful comparison of measurements and computations, one can extract controversial bandstructure parameters such as the band offset. © Springer Science+Business Media B.V. 2007.
• Thränhardt, A., Koch, S. W., Hader, J., & Moloney, J. V. (2006). Carrier dynamics in quantum well lasers. Optical and Quantum Electronics, 38(4-6), 361-368.
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  Abstract: A fully microscopic theory is used to perform an analysis of carrier-carrier and carrier-LO phonon scattering in semiconductor quantum wells, focussing on the high-density case relevant for laser structures. A large variance of scattering times is observed depending on the material parameters, apparently contradicting popular belief in some cases. For instance, carrier-carrier scattering may slow down when the carrier density is increased. Electron-hole scattering times are found to be on the same order of magnitude as carrier-phonon scattering, making the introduction of a separate electron and hole temperature necessary. Heating by optical pumping is investigated and plasma cooling is shown to be possible by optical pumping of the laser structure. © Springer 2006.
• Thränhardt, A., Meier, T., Reichelt, M., Schlichenmaier, C., Pasenow, B., Kuznetsova, I., Becker, S., Stroucken, T., Hader, J., Zakharian, A. R., Moloney, J. V., Chow, W. W., & Koch, S. W. (2006). Microscopic modeling of the optical properties of semiconductor nanostructures. Journal of Non-Crystalline Solids, 352(23-25), 2480-2483.
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  Abstract: A brief overview of a consistent microscopic approach to model the optical and electronic properties of semiconductor nanostructures is presented. Coupled semiconductor Bloch and Maxwell equations are used to investigate the performance of semiconductor microcavity structures, photonic band gap systems, and lasers. The predictive potential of the microscopic theory is demonstrated for several examples of practical importance. Optical gain and output characteristics are computed for modern vertical external cavity surface emitting laser structures. It is shown how design flexibilities can be used to optimize the device performance. Nanostructures are proposed where semiconductor quantum wells are embedded in one-dimensional photonic crystals. For field modes spectrally below the photonic band edge it is shown that the optical gain and absorption can be enhanced by more than one order of magnitude over the value of the homogeneous medium. The increased gain can be used for laser action by placing quantum wells and a suitably designed photonic crystal structure inside a microcavity. © 2006 Elsevier B.V. All rights reserved.
• Xie, Y., Zakharian, A. R., Moloney, J. V., & Mansuripur, M. (2006). Optical transmission at oblique incidence through a periodic array of sub-wavelength slits in a metallic host. Optics Express, 14(22), 10220-10227.
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  PMID: 19529417;Abstract: Using the Bloch modes of a periodic, semi-infinite array of slits in a metallic host, we study the transmission of obliquely incident plane-waves through sub-wavelength slits. Matching the tangential E- and H-fields at the entrance facet of the periodic structure yields the complex amplitudes of the various Bloch modes, which exist and propagate within the slit array independently of each other. The computational scheme is robust, convergence is rapid, and a good match at the boundaries is obtained in every case. The regions examined in some detail include the vicinity of the Wood anomaly (where new diffraction orders appear/disappear on the horizon), the neighborhood of a point where surface plasmon polaritons (SPPs) are excited, and an ordinary situation in which the incidence angle is far from the angles that invoke Wood's anomaly or cause the excitation of SPPs. Field distributions and energy flow diagrams in and around the slits reveal the existence of transmission minima (and reflection maxima) at incidence angles associated with the excitation of SPPs. ©2006 Optical Society of America.
• Xie, Y., Zakharian, A. R., Moloney, J. V., & Mansuripur, M. (2006). Optical transmission at oblique incidence through a periodic array of sub-wavelength slits in a metallic host. Optics express, 14(22), 10220--10227.
• Xie, Y., Zakharian, A. R., Moloney, J. V., & Mansuripur, M. (2006). Transmission of light through periodic arrays of sub-wavelength slits in metallic hosts. Optics Express, 14(14), 6400-6413.
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  PMID: 19516818;Abstract: Using Bloch modes to study the extraordinary transmission of light through a periodic array of slits in a metallic host, we discuss the differing roles of surface plasmon polaritons and Wood's anomalies in the observed behavior of such structures. Under certain circumstances, the first few excited modes appear to play a decisive role in determining the transmission efficiency of the array. Surface plasmon excitations tend to reduce the transmissivity of a semi-infinitely thick slit array, yet, paradoxically, the same reduction can account for enhanced transmission in an array of finite thickness τ, provided that τ is tuned to a Fabry-Perot-like resonance between the entrance and exit facets of the slit array. At the Wood anomaly, power redistribution produces sharp peaks in the diffraction efficiencies of various reflected and transmitted orders of the semi-infinite structure. With skew incidence, the degenerate states split, resulting in two peaks and two valleys, as observed by Wood in his 1902 experiments. © 2006 Optical Society of America.
• Xie, Y., Zakharian, A., Moloney, J., & Mansuripur, M. (2006). Transmission of light through periodic arrays of sub-wavelength slits in metallic hosts. Optics express, 14(14), 6400--6413.
• Zakharian, A. R., Polynkin, P., Mansuripur, M., & Moloney, J. V. (2006). Single-beam trapping of micro-beads in polarized light: Numerical simulations. Optics Express, 14(8), 3660-3676.
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  PMID: 19516513;Abstract: Using numerical solutions of Maxwell's equations in conjunction with the Lorentz law of force, we compute the electromagnetic force distribution in and around a dielectric micro-sphere trapped by a focused laser beam. Dependence of the optical trap's stiffness on the polarization state of the incident beam is analyzed for particles suspended in air or immersed in water, under conditions similar to those realized in practical optical tweezers. A comparison of the simulation results with available experimental data reveals the merit of one physical model relative to two competing models; the three models arise from different interpretations of the same physical picture. © 2006 Optical Society of America.
• Zakharian, A., Brio, M., Dineen, C., & Moloney, J. (2006). Second-order accurate FDTD space and time grid refinement method in three space dimensions. Photonics Technology Letters, IEEE, 18(11), 1237--1239.
• Zakharian, A., Brio, M., Dineen, C., Moloney, J., & others, . (2006). Stability of 2D FDTD algorithms with local mesh refinement for Maxwell's equations. Communications in Mathematical Sciences, 4(2), 345--374.
• Zakharian, A., Polynkin, P., Mansuripur, M., & Moloney, J. (2006). Single-beam trapping of micro-beads in polarized light: Numerical simulations. Optics express, 14(8), 3660--3676.
• Adomavi\ccius, R., Molis, G., Krotkus, A., Sirutkaitis, V., Djie, H., Ooi, B., Aimez, V., Luo, J., Peng, J., Cao, Y., & others, . (2005). LASERS, OPTICS, AND OPTOELECTRONICS. Applied Physics Letters, 87(26).
• Dineen, C., Förstner, J., Zakharian, A. R., Moloney, J. V., & Koch, S. W. (2005). Electromagnetic field structure and normal mode coupling in photonic crystal nanocavities. Optics Express, 13(13), 4980-4985.
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  PMID: 19498486;Abstract: The electromagnetic field of a high-quality photonic crystal nanocavity is computed using the finite difference time domain method. It is shown that a separatrix occurs in the local energy flux discriminating between predominantly near and far field components. Placing a two-level atom into the cavity leads to characteristic field modifications and normal-mode splitting in the transmission spectra. © 2005 Optical Society of America.
• Fan, L., Fallahi, M., Hader, J., Zakharian, A. R., Kolesik, M., Moloney, J. V., Qiu, T., Schülzgen, A., Peyghambarian, N., Stolz, W., Koch, S. W., & Murray, J. T. (2005). Over 3 W high-efficiency vertical-external-cavity surface-emitting lasers and application as efficient fiber laser pump sources. Applied Physics Letters, 86(21), 1-3.
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  Abstract: We report on the design and fabrication of high-power, high-brightness diode-pumped vertical-external-cavity surface-emitting lasers. Over 3 W continuous wave fundamental transverse mode (TEM00) output at 980 nm with a high slope efficiency of 44% is demonstrated at room temperature. The diffraction-limited beam with M2 factor of 1.15 at high-power operation is achieved. A vertical-external-cavity surface-emitting laser operating near 976 nm with a diffraction-limited beam is used to pump the core of 3 cm long ErYb -codoped single-mode phosphate fiber lasers. An output power in excess of 250 mW at 1535 nm with a slope efficiency of 29% is obtained without any cooling. © 2005 American Institute of Physics.
• Fan, L., Fallahi, M., Hader, J., Zakharian, A., Kolesik, M., Moloney, J., Qiu, T., Schulzgen, A., Peyghambarian, N., Stolz, W., & others, . (2005). Over 3 W high-efficiency vertical-external-cavity surface-emitting lasers and application as efficient fiber laser pump sources. Applied Physics Letters, 86(21), 211116--211116.
• Fan, L., Hader, J., Schillgalies, M., Fallahi, M., Zakharian, A. R., Moloney, J. V., Bedford, R., Murray, J. T., Koch, S. W., & Stolz, W. (2005). High-power optically pumped VECSEL using a double-well resonant periodic gain structure. IEEE Photonics Technology Letters, 17(9), 1764-1766.
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  Abstract: We present the design and fabrication of an optically pumped vertical-external-cavity surface-emitting lasers with double-well resonant periodic gain structure. Each double-well consists of two 4-nm-thick InGaAs strained quantum wells. The double-well provides optimum overlap between the quantum wells and the antinodes of the standing wave of laser signal at high-power and high-temperature operation. The structure is more tolerant to variation of the growth, processing, and operating temperature for maintaining high modal gain. For a 230-μm diameter pump spot, over 4-W continuous-wave output with a slope efficiency of 39% is demonstrated at 30 °C without thermal rollover. © 2005 IEEE.
• Fan, L., Hader, J., Schillgalies, M., Fallahi, M., Zakharian, A. R., Moloney, J. V., Bedford, R., Murray, J. T., Koch, S. W., & Stolz, W. (2005). High-power optically pumped VECSEL using a double-well resonant periodic gain structure. Photonics Technology Letters, IEEE, 17(9), 1764--1766.
• Gundu, K., Brio, M., & Moloney, J. (2005). A mixed high-order vector finite element method for waveguides: convergence and spurious mode studies. International Journal of Numerical Modelling: Electronic Networks, Devices and Fields, 18(5), 351--364.
• Hader, J., Moloney, J. V., & Koch, S. W. (2005). Abc's of semiconductor lasers. Fact or fiction?. Frontiers in Optics. doi:10.1364/fio.2005.fmf5
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  It is demonstrated that fully microscopic many-body models are required for a correct description of the dominant carrier loss-processes in semiconductor lasers, spontaneous emission and Auger recombination, and that they are able to quantitatively predict these losses. The density dependence of the losses assumed in semiempirical aproaches, J=AN+BN2+CN3, is shown to break down already near transparency. For the spontaneous emission it is shown to decrease from quadratic to linear (BN), Auger rates are shown to increase only quadratically (CN2) or even less.
• Hader, J., Moloney, J. V., & Koch, S. W. (2005). Microscopic evaluation of spontaneous emission- and Auger-processes in semiconductor lasers. IEEE Journal of Quantum Electronics, 41(10), 1217-1226.
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  Abstract: A fully microscopic approach is used to compute the losses in semiconductor lasers due to spontaneous emission and Auger recombination. The model is based on the semiconductor-Bloch equations and generalized quantum-Boltzmann type scattering equations in the second Born-Markov approximation. As input the theory only needs the structural layout and fundamental bulk-bandstructure parameters. It is demonstrated that such a comprehensive model that calculates gain/ absorption, spontaneous emission and Auger processes on the same microscopic level can reliably predict these usually dominant loss processes. Examples of the results are compared to measurements on lasers in the 1.3-1.5 μm range demonstrating very good agreement without empirical fitting. © 2005 IEEE.
• Hader, J., Moloney, J. V., & Koch, S. W. (2005). Microscopic evaluation of spontaneous emission-and Auger-processes in semiconductor lasers. Quantum Electronics, IEEE Journal of, 41(10), 1217--1226.
• Hader, J., Moloney, J. V., & Koch, S. W. (2005). Supression of carrier recombination in semiconductor lasers by phase-space filling. Applied Physics Letters, 87(20), 1-3.
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  Abstract: A fully microscopic model is used to calculate the carrier losses in semiconductor lasers due to Auger recombination and spontaneous emission. The results show that the commonly assumed power-law dependencies of these loss processes on the plasma density break down already below the transparency point. Most significantly, the density dependent increase of the spontaneous emission changes from quadratic to linear, while the increase of the Auger recombination is reduced from cubic to approximately quadratic or even less. © 2005 American Institute of Physics.
• Hader, J., Moloney, J., & Koch, S. (2005). Supression of carrier recombination in semiconductor lasers by phase-space filling. Applied Physics Letters, 87(20), 201112.
• Hoyer, W., Knorr, A., Moloney, J., Wright, E., Kira, M., & Koch, S. (2005). Photoluminescence and terahertz emission from femtosecond laser-induced plasma channels. Physical review letters, 94(11), 115004.
• Hoyer, W., Moloney, J., Wright, E., Kira, M., & Koch, S. (2005). Thermal wakefield oscillations of laser-induced plasma channels and their spectral signatures in luminescence. Journal of Physics: Conference Series, 11(1), 153.
• Kano, P. O., Brio, M., Moloney, J. V., & others, . (2005). Application of Weeks method for the numerical inversion of the Laplace transform to the matrix exponential. Communications in Mathematical Sciences, 3(3), 335--372.
• Kolesik, M., Wright, E., & Moloney, J. (2005). Interpretation of the spectrally resolved far field of femtosecond pulses propagating in bulk nonlinear dispersive media. Optics express, 13(26), 10729--10741.
• Li, L., Li, H., Qiu, T., Temyanko, V. L., Morrell, M. M., Schülzgen, A., Mafi, A., Moloney, J. V., & Peyghambarian, N. (2005). 3-Dimensional thermal analysis and active cooling of short-length high-power fiber lasers. Optics Express, 13(9), 3420-3428.
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  PMID: 19495244;Abstract: A fully 3-dimensional finite element model has been developed that simulates the internal temperature distribution of short-length high-power fiber lasers. We have validated the numerical model by building a short, cladding-pumped, Er-Yb-codoped fiber laser and measuring the core temperature during laser operation. A dual-end-pumped, actively cooled, fiber laser has generated >11 W CW output power at 1535 nm from only 11.9 cm of active fiber. Simulations indicate power-scaling possibilities with improved fiber and cooling designs. © 2005 Optical Society of America.
• Li, L., Li, H., Qiu, T., Temyanko, V., Morrell, M., Sch\"ulzgen, A., Mafi, A., Moloney, J., & Peyghambarian, N. (2005). 3-Dimensional thermal analysis and active cooling of short-length high-power fiber lasers. Optics express, 13(9), 3420--3428.
• Li, L., Sch\"ulzgen, A., Temyanko, V., Li, H., Sabet, S., Morrell, M., Mafi, A., Moloney, J., & Peyghambarian, N. (2005). Investigation of modal properties of microstructured optical fibers with large depressed-index cores. Optics letters, 30(24), 3275--3277.
• Li, L., Sch\"ulzgen, A., Temyanko, V., Qiu, T., Morrell, M., Wang, Q., Mafi, A., Moloney, J., & Peyghambarian, N. (2005). Short-length microstructured phosphate glass fiber lasers with large mode areas. Optics letters, 30(10), 1141--1143.
• Li, L., Schulzgen, A., Temyanko, V. L., Morrell, M. M., Sabet, S., Li, H., Moloney, J. V., & Peyghambarian, N. (2005). High-Power Short-Length Microstructured Phosphate Fiber Lasers With Large Mode Areas. Frontiers in Optics. doi:10.1364/fio.2005.jtuc50
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  We report short-length high-power microstructured phosphate fiber lasers. The heavily Er-Yb-codoped core area is ~500 μm2 and ~8 W CW output at 1.5 μm is demonstrated from a 10-cm cladding-pumped fiber laser.
• Li, L., Schülzgen, A., Temyanko, V. L., Li, H., Sabet, S., Morrell, M. M., Mafi, A., Moloney, J. V., & Peyghambarian, N. (2005). Investigation of modal properties of microstructured optical fibers with large depressed-index cores. Optics Letters, 30(24), 3275-3277.
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  PMID: 16389803;Abstract: We present what is, to the best of our knowledge, the first systematic study on how negative core-cladding index difference influences microstructured optical fiber's modal behavior. Single-mode lasing has been realized for short-length cladding-pumped phosphate glass microstructured fibers with large depressed-index Er3+-Yb3+-codoped cores. © 2005 Optical Society of America.
• Liu, T., Fallahi, M., Mansuripur, M., Zakharian, A. R., & Moloney, J. V. (2005). Intersection of nonidentical optical waveguides based on photonic crystals. Optics Letters, 30(18), 2409-2411.
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  PMID: 16196335;Abstract: An intersection based on photonic crystal coupled resonator optical waveguides is proposed and analyzed. The two waveguides are designed to have different transmission bands without overlap, which enables light in the two corresponding bands to propagate through the intersection with no cross talk and with excellent transmission. The MIT Photonic-Bands code is used to calculate the band structures of photonic crystal waveguides. The finite-difference time-domain method is used to simulate the relevant structures. © 2005 Optical Society of America.
• Liu, T., Fallahi, M., Mansuripur, M., Zakharian, A. R., & Moloney, J. V. (2005). Intersection of nonidentical optical waveguides based on photonic crystals. Optics letters, 30(18), 2409--2411.
• Liu, T., Zakharian, A. R., Fallahi, M., Moloney, J. V., & Mansuripur, M. (2005). Design of a compact photonic-crystal-based polarizing beam splitter. IEEE Photonics Technology Letters, 17(7), 1435-1437.
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  Abstract: A compact polarizing beam splitter based on a photonic crystal (PC) directional coupler with a triangular lattice of air holes is designed and simulated. In the employed PC structure, transverse-electric (TE) light is confined with the photonic bandgap effect, while transverse-magnetic (TM) light is guided through an index-like effect. Due to the different guiding mechanisms, TM and TE light have strikingly different beat lengths, which is utilized to separate the two polarizations in a directional coupler no longer than 24.2 μm. The two-dimensional finite-difference time-domain method of computation is used to evaluate the device performance. The extinction ratios are found to be around 20 dB for both TE and TM polarized light. © 2005 IEEE.
• Liu, T., Zakharian, A. R., Fallahi, M., Moloney, J. V., & Mansuripur, M. (2005). Design of a compact photonic-crystal-based polarizing beam splitter. Photonics Technology Letters, IEEE, 17(7), 1435--1437.
• Mafi, A., & Moloney, J. V. (2005). Beam quality of photonic-crystal fibers. Journal of Lightwave Technology, 23(7), 2267-2270.
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  Abstract: In this paper, we investigate the beam quality of photonic-crystal fibers (PCFs) with one, three, and seven missing airholes. The beam quality factor M2 of a PCF is generally larger than unity, even if it is single mode. The results are especially important for the design and measurements of single-mode PCF lasers. A comparison between an M2 measurement of the laser beam and the reported numbers can establish whether a PCF laser is operating as single mode or is contaminated by higher order modes. © 2005 IEEE.
• Mafi, A., & Moloney, J. V. (2005). Beam quality of photonic-crystal fibers. Journal of lightwave technology, 23(7), 2267.
• Mafi, A., & Moloney, J. V. (2005). Shaping modes in multicore photonic crystal fibers. IEEE Photonics Technology Letters, 17(2), 348-350.
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  Abstract: We explore the possibility of devising custom-shaped modes for multicore photonic crystal fibers by manipulating their geometrical structures. We present a recipe for constructing custom-shaped modes based on perturbation theory of coupled modes and the finite element method. © 2005 IEEE.
• Mafi, A., & Moloney, J. V. (2005). Shaping modes in multicore photonic crystal fibers. IEEE photonics technology letters, 17(2), 348--350.
• Mansuripur, M., Xie, Y., Zakharian, A. R., & Moloney, J. V. (2005). Transmission of light through slit apertures in metallic films. IEEE Transactions on Magnetics, 41(2), 1012-1015.
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  Abstract: Transmission of polarized light through subwavelength slit apertures is studied based on the electromagnetic field distributions obtained in finite difference time domain computer simulations. The results show the existence of a cutoff for E∥ and a strong transmission (with no cutoff) for E⊥, where ∥ and ⊥ refer to the direction of the incident E-field relative to the long axis of the slit. Interference between the charges and currents induced in the vicinity of two adjacent slits is shown to result in enhanced transmission through both slits when the slits are separated by about one half of one wavelength.
• Mansuripur, M., Xie, Y., Zakharian, A. R., & Moloney, J. V. (2005). Transmission of light through slit apertures in metallic films. Magnetics, IEEE Transactions on, 41(2), 1012--1015.
• Mansuripur, M., Zakharian, A. R., & Moloney, J. V. (2005). Radiation pressure on a dielectric wedge. Opt. Express, 13, 2064--2074.
• Mansuripur, M., Zakharian, A. R., & Moloney, J. V. (2005). Radiation pressure on a dielectric wedge. Optics Express, 13(6), 2064-2074.
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  PMID: 19495091;Abstract: The force of electromagnetic radiation on a dielectric medium may be derived by a direct application of the Lorentz law of classical electrodynamics. While the light's electric field acts upon the (induced) bound charges in the medium, its magnetic field exerts a force on the bound currents. We use the example of a wedge-shaped solid dielectric, immersed in a transparent liquid and illuminated at Brewster's angle, to demonstrate that the linear momentum of the electromagnetic field within dielectrics has neither the Minkowski nor the Abraham form; rather, the correct expression for momentum density has equal contributions from both. The time rate of change of the incident momentum thus expressed is equal to the force exerted on the wedge plus that experienced by the surrounding liquid. © 2005 Optical Society of America.
• Moloney, J. V. (2005). Modeling photonic structures - nanophotonics, vecsels, x-waves and light strings. Frontiers in Optics. doi:10.1364/fio.2005.fmf1
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  We will discuss how computational photonics impacts the design and fabrication of future micro- and nano-scale optical on-chip devices, high power, high brightness semiconductor lasers and the study of ultra-fast, highly nonlinear pulse propagation effect.
• Pasenow, B., Reichelt, M., Stroucken, T., Meier, T., Koch, S. W., Zakharian, A. R., & Moloney, J. V. (2005). Enhanced light-matter interaction in semiconductor heterostructures embedded in one-dimensional photonic crystals. JOSA B, 22(9), 2039--2048.
• Pasenow, B., Reichelt, M., Stroucken, T., Meier, T., Koch, S. W., Zakharian, A. R., & Moloney, J. V. (2005). Enhanced light-matter interaction in semiconductor heterostructures embedded in one-dimensional photonic crystals. Journal of the Optical Society of America B: Optical Physics, 22(9), 2039-2048.
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  Abstract: The optical properties of semiconductor quantum wells embedded in one-dimensional photonic crystal structures are analyzed by a self-consistent solution of Maxwell's equations and a microscopic many-body theory of the material excitations. For a field mode spectrally below the photonic band edge it is shown that the optical absorption and gain are enhanced, exceeding by more than 1 order of magnitude the values of a homogeneous medium. For the photonic crystal structure inside a microcavity the gain increases superlinearly with the number of wells and for more than five wells exceeds the gain of a corresponding vertical-cavity surface-emitting laser. © 2005 Optical Society of America.
• Polynkin, P., Polynkin, A., Mansuripur, M., Moloney, J., & Peyghambarian, N. (2005). Compact single-frequency fiber laser oscillator emits watts-level output power at 1.5 mm. Optics and Photonics News, 16(12 SPEC. ISS.), 27-.
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  Abstract: The design of an all-fiber single-frequency Er-Yb laser oscillator, that produces 1.9 W of direct output power at 1.5 μm, is described. The 11-cm-long, side-pumped active fiber section is composed of soft phosphate glass, which allows a massive doping concentration, 1 weight percent of Er and 8 weight percent of Yb. An active fiber, used as a gain medium of a multimode fiber laser, can produce as much as 1.33 W of output power per centimeter of fiber. To improve the longitudinal mode selection in the laser, a Bragg grating is spliced behind the primary single-mode reflector.
• Polynkin, P., Polynkin, A., Mansuripur, M., Moloney, J., & Peyghambarian, N. (2005). Single-frequency laser oscillator with watts-level output power at 1.5 $\mu$m by use of a twisted-mode technique. Optics letters, 30(20), 2745--2747.
• Polynkin, P., Polynkin, A., Mansuripur, M., Moloney, J., & Peyghambarian, N. (2005). Single-frequency laser oscillator with watts-level output power at 1.5 μm by use of a twisted-mode technique. Optics Letters, 30(20), 2745-2747.
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  PMID: 16252761;Abstract: We report an all-fiber laser oscillator producing as much as 1.9 W of single-frequency direct output at 1.5 μm. Spatial gain hole burning in the active fiber has been eliminated by use of a twisted-mode cavity approach. The two short pieces of a polarization-maintaining fiber that were spliced to the ends of the active fiber served as ultracompact quarter-wave plates. To our knowledge, the use of such a wave plate to manipulate the polarization state of light inside a fiber laser cavity is reported here for the first time. The laser output is linearly polarized and delivered through a polarization-maintaining fiber pigtail. We believe that the output power of our laser is the highest among all single-frequency fiber laser oscillators reported to date.
• Qiu, T., Suzuki, S., Sch\"ulzgen, A., Li, L., Polynkin, A., Temyanko, V., Moloney, J. V., & Peyghambarian, N. (2005). Generation of watt-level single-longitudinal-mode output from cladding-pumped short fiber lasers. Optics letters, 30(20), 2748--2750.
• Qiu, T., Suzuki, S., Schülzgen, A., Li, L., Polynkin, A., Temyanko, V., Moloney, J. V., & Peyghambarian, N. (2005). Generation of watt-level single-longitudinal-mode output from cladding-pumped short fiber lasers. Optics Letters, 30(20), 2748-2750.
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  PMID: 16252762;Abstract: We generate as much as 1.6 W of continuous-wave 1550 nm single-longitudinal-mode output from a cladding pumped Er-Yb codoped phosphate fiber laser. This power is to our knowledge among the highest in single-longitudinal-mode fiber lasers. The narrowband fiber Bragg grating output coupler is demonstrated to be an effective element for providing the single-longitudinal-mode selection. © 2005 Optical Society of America.
• Richter, M., Schaarschmidt, M., Knorr, A., Hoyer, W., Moloney, J., Wright, E., Kira, M., & Koch, S. (2005). Quantum theory of incoherent THz emission of an interacting electron-ion plasma. Physical Review A, 71(5), 053819.
• S\orensen, M. P., Webb, G. M., Brio, M., & Moloney, J. V. (2005). Kink shape solutions of the Maxwell-Lorentz system. Physical Review E, 71(3), 036602.
• Schlichenmaier, C., Gruning, H., Thranhardt, A., Klar, P., Kunert, B., Volz, K., Stolz, W., Heimbrodt, W., Meier, T., Koch, S., & others, . (2005). Type I-type II transition in InGaAs--GaNAs heterostructures. Applied Physics Letters, 86(8), 081903--081903.
• Schlichenmaier, C., Grüning, H., Thränhardt, A., Klar, P. J., Kunert, B., Volz, K., Stolz, W., Heimbrodt, W., Meier, T., Koch, S. W., Hader, J., & Moloney, J. V. (2005). Type I-type II transition in InGaAs-GaNAs heterostructures. Applied Physics Letters, 86(8), 1-3.
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  Abstract: Optical interband transitions in a series of In0.23 Ga0.77 As-Ga Nx As1-x quantum well samples are investigated. For changing nitrogen content, a type I-type II transition is identified by a detailed analysis of photoluminescence and photoreflectance spectra. Experimental results are compared systematically with spectra calculated by a microscopic theory. A valence band offset parameter of (1.5±0.5) eV is extracted for this heterostructure system. © 2005 American Institute of Physics.
• Schlichenmaier, C., Thr\"anhardt, A., Meier, T., Koch, S., Chow, W., Hader, J., & Moloney, J. (2005). Gain and carrier losses of (GaIn)(NAs) heterostructures in the 1300-1550 nm range. Applied Physics Letters, 87(26), 1109.
• Schlichenmaier, C., Thränhardt, A., Meier, T., Koch, S. W., Chow, W. W., Hader, J., & Moloney, J. V. (2005). Gain and carrier losses of (GaIn)(NAs) heterostructures in the 1300-1550 nm range. Applied Physics Letters, 87(26), 1-3.
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  Abstract: A microscopic model is used to analyze gain and loss properties of (GaIn) (NAs) GaAs quantum wells in the 1.3-1.55 μm range, including Auger and radiative recombination. The calculations show that, as long as good material quality can be achieved, growing highly compressively strained samples is preferable due to their specific band structure properties. Optimum laser operation is possible slightly above a peak gain of 1000 cm-1. © 2005 American Institute of Physics.
• Thr\"anhardt, A., Kuznetsova, I., Schlichenmaier, C., Koch, S., Shterengas, L., Belenky, G., Yeh, J., Mawst, L., Tansu, N., Hader, J., & others, . (2005). Nitrogen incorporation effects on gain properties of GaInNAs lasers: Experiment and theory. Applied Physics Letters, 86(20), 201117.
• Thränhardt, A., Kuznetsova, I., Schlichenmaier, C., Koch, S. W., Shterengas, L., Belenky, G., Yeh, J. -., Mawst, L. J., Tansu, N., Hader, J., Moloney, J. V., & Chow, W. W. (2005). Nitrogen incorporation effects on gain properties of GaInNAs lasers: Experiment and theory. Applied Physics Letters, 86(20), 1-3.
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  Abstract: Gain properties of GaInNAs lasers with different nitrogen concentrations in the quantum wells are investigated experimentally and theoretically. Whereas nitrogen incorporation induces appreciable modifications in the spectral extension and the carrier density dependence of the gain, it is found that the linewidth enhancement factor is reduced by inclusion of nitrogen, but basically unaffected by different nitrogen content due to the balancing between gain and index changes. © 2005 American Institute of Physics.
• Turnbull, G., Carleton, A., Tahraouhi, A., Krauss, T., Samuel, I., Barlow, G., Hoffman, D., Hood, A., Wei, Y., Gin, A., & others, . (2005). LASERS, OPTICS, AND OPTOELECTRONICS. Appl. Phys. Lett, 87(20), 202104.
• Xie, Y., Zakharian, A. R., Moloney, J. V., & Mansuripur, M. (2005). Transmission of light through a periodic array of slits in a thick metallic film. Optics Express, 13(12), 4485-4491.
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  PMID: 19495363;Abstract: Finite-difference-time-domain (FDTD) computer simulations reveal interesting features of the transmission of a linearly polarized plane-wave through a periodic array of sub-wavelength slits in a thick metal film (incident E-field perpendicular to the slits' long axis). The results show that slit transmission has a quasi-periodic dependence on both the film thickness and the period of the slits. This indicates that resonant surface waves excited at the top and bottom facets of the metal film as well as resonant guided modes along the depth of the slits play major roles in determining the transmission efficiency of the array. When the slit periodicity is an integer-multiple of the surfacc-plasmon wavelength, transmission drops to zero regardless of film thickness; in other words, excitation of surface plasmons reduces the transmission efficiency. When the slit periodicity deviates from the aforementioned value, maximum transmission through the slits is achieved by adjusting the film thickness. In the thickness dimension, transmission maxima occur periodically, with a period of half the effective wavelength of the guided mode in each slit waveguide. Optimum transmission is thus achieved by simultaneously adjusting the film thickness and the period of the slits. Computed field profiles clarify the role played by the induced surface charges and currents in enhancing the light's coupling efficiency into and out of the slits. © 2005 Optical Society of America.
• Xie, Y., Zakharian, A., Moloney, J., & Mansuripur, M. (2005). Transmission of light through a periodic array of slits in a thick metallic film. Optics Express, 13(12), 4485--4491.
• Zakharian, A. R., Hader, J., Moloney, J. V., & Koch, S. W. (2005). Optical gain enhancement in VECSELs with photonic-band-edge active region design. Frontiers in Optics. doi:10.1364/fio.2005.fmf3
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  Using a numerical model we evaluate the enhancement of the optical gain due to the small group-velocity of the light near the band-edge of a multiple quantum well periodic structure of an optically pumped VECSEL.
• Zakharian, A. R., Hader, J., Moloney, J. V., & Koch, S. W. (2005). VECSEL threshold and output power-shutoff dependence on the carrier recombination rates. IEEE Photonics Technology Letters, 17(12), 2511-2513.
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  Abstract: We compute the lasing threshold and thermally driven power-shutoff characteristics of optically pumped vertical-external-cavity surface-emitting lasers. Using a quantitative numerical model, variations in the threshold and shutoff power levels are contrasted for the two approaches to the computation of the carrier recombination rates: using the AN + BN2 + CN3 model with the temperature and carrier density independent coefficients, versus using recombination rates precomputed within the framework of the microscopic many-body theory. © 2005 IEEE.
• Zakharian, A. R., Mansuripur, M., & Moloney, J. V. (2005). Radiation pressure and the distribution of electromagnetic force in dielectric media. Optics Express, 13(7), 2321-2336.
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  PMID: 19495121;Abstract: Using the Finite-Difference-Time-Domain (FDTD) method, we compute the electromagnetic field distribution in and around dielectric media of various shapes and optical properties. With the aid of the constitutive relations, we proceed to compute the bound charge and bound current densities, then employ the Lorentz law of force to determine the distribution of force density within the regions of interest. For a few simple cases where analytical solutions exist, these solutions are found to be in complete agreement with our numerical results. We also analyze the distribution of fields and forces in more complex systems, and discuss the relevance of our findings to experimental observations. In particular, we demonstrate the single-beam trapping of a dielectric micro-sphere immersed in a liquid under conditions that are typical of optical tweezers. © 2005 Optical Society of America.
• Zakharian, A., Hader, J., Moloney, J., & Koch, S. (2005). VECSEL threshold and output power-shutoff dependence on the carrier recombination rates. Photonics Technology Letters, IEEE, 17(12), 2511--2513.
• Zakharian, A., Mansuripur, M., & Moloney, J. (2005). Radiation pressure and the distribution of electromagnetic force in dielectric media. Optics Express, 13(7), 2321--2336.
• D’Ercole, A., Maeda, M., Palange, E., Ishitobi, H., DelRe, E., Sekkat, Z., Ciattoni, A., Kawata, S., Crosignani, B., Netti, C., Agranat, A., Charlton, M., Cluzel, B., Zoorob, M., G\'erard, D., Parker, G., Picard, E., Jin, S., Charvolin, T., , Sweeney, S., et al. (2004). LASERS, OPTICS, AND OPTOELECTRONICS. Appl. Phys. Lett, 85(3).
• Gerhardt, N. C., Hofmann, M. R., Hader, J., Moloney, J. V., Koch, S. W., & Riechert, H. (2004). Linewidth enhancement factor and optical gain in (GaIn)(NAs)/GaAs lasers. Applied Physics Letters, 84(1), 1-3.
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  Abstract: Measurements and microscopic calculations of the α-factor in (GaIn)(NAs) quantum well lasers were discussed. Data was obtained from the shift of the Fabry-Perot modes with injection current was used to eliminate temperature-dependent artifacts. The molecular beam epitaxy was grown 350 μm long ridge-waveguide laser structure for the experiment. It was found that the value of α at the laser emission wavelength in this structure is around 2.5 +/-0.4 and remains constant with carrier density variations for a fixed emission wavelength.
• Gerhardt, N., Hofmann, M., Hader, J., Moloney, J., Koch, S., & Riechert, H. (2004). Linewidth enhancement factor and optical gain in (GaIn)(NAs)/GaAs lasers. Applied physics letters, 84(1), 1--3.
• Hader, J., Moloney, J. V., & Koch, S. W. (2004). Erratum: Microscopic Theory of Gain, Absorption, and Refractive Index in Semiconductor Laser Materials - Influence of Conduction-Band Nonparabolicity and Coulomb-Induced Intersubband Coupling (IEEE Journal of Quantum Electronics (Dec. 1999) 35 (1878-1886)). IEEE Journal of Quantum Electronics, 40(3), 330-331.
• Hader, J., Moloney, J. V., & Koch, S. W. (2004). Structural dependence of carrier capture time in semiconductor quantum-well lasers. Applied Physics Letters, 85(3), 369-371.
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  Abstract: Carrier capture for InGaPA-based and InGaAlAs-based multiple quantum-well structures for the 1.55 μm wavelength regime was investigated. The capture time and dynamics were found to be governed by transitions between quantum states that were delocalized throughout the whole structure. It was found that the concept of a unique capture time was often not appropriate, since this time was not a constant that is characteristicc for a given quantum well. It was shown that the capture can be made faster by using structures with a larger ratio of well- to barrier-material.
• Hader, J., Moloney, J., & Koch, S. (2004). Corrections to \&\# 8220; Microscopic Theory of Gain, Absorption, and Refractive Index in Semiconductor Laser Materials\&\# 8212; Influence of Conduction-Band Nonparabolicity and Coulomb-Induced Intersubband Coupling\&\# 8221. Quantum Electronics, IEEE Journal of, 40(3), 330--332.
• Hader, J., Moloney, J., & Koch, S. (2004). Structural dependence of carrier capture time in semiconductor quantum-well lasers. Applied Physics Letters, 85(3), 369--371.
• Hoffmann, S., Hofmann, M., Br\"undermann, E., Havenith, M., Matus, M., Moloney, J., Moskalenko, A., Kira, M., Koch, S., Saito, S., & others, . (2004). Four-wave mixing and direct terahertz emission with two-color semiconductor lasers. Applied physics letters, 84(18), 3585--3587.
• Hoffmann, S., Hofmann, M., Bründermann, E., Havenith, M., Matus, M., Moloney, J. V., Moskalenko, A. S., Kira, M., Koch, S. W., Saito, S., & Sakai, K. (2004). Four-wave mixing and direct terahertz emission with two-color semiconductor lasers. Applied Physics Letters, 84(18), 3585-3587.
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  Abstract: The four-wave mixing in a semiconductor laser configured to emit on two wavelengths simultaneously was analyzed. It was shown that the four-wave mixing sidebands exist up to 4 THz stemming from a modulation of the carrier plasma at the difference frequency of the two laser modes. The tunable THz radiation at the difference frequency from the laser device itself suggesting a scheme for a tunable THz source was generated and detected. The results show that the corresponding difference frequency in the THz regime is emitted directly out of the laser diode.
• Kano, P., Kouznetsov, D., Moloney, J. V., & Brio, M. (2004). Slab delivery of incoherent pump light to double-clad fiber amplifiers: numerical simulations. IEEE journal of quantum electronics, 40(9), 1301--1305.
• Kolesik, M., & Moloney, J. (2004). Nonlinear optical pulse propagation simulation: From Maxwell’s to unidirectional equations. Physical Review E, 70(3), 036604.
• Kolesik, M., & Moloney, J. V. (2004). Nonlinear optical pulse propagation simulation: From Maxwell's to unidirectional equations. Physical Review E - Statistical, Nonlinear, and Soft Matter Physics, 70(3 2), 036604-1-036604-11.
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  PMID: 15524653;Abstract: The derivation of spatial and time-domian versions of the undirectional pulse propagation equation (UPPE) was presented. The gap between the numerical Maxwell's equation solvers and a family of undirectional propagation equations was removed by the equation. The UPPE was modified suitably for the ultrathin optical waveguides, such as submicron silica wires. A z-propagated UPPE suitable for strandlike waveguides with transverse dimensions comparable to the wavelength was also elaborated.
• Kolesik, M., & Moloney, J. V. (2004). Self-healing femtosecond light filaments. Optics Letters, 29(6), 590-592.
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  PMID: 15035480;Abstract: A recent experiment [Appl. Phys. Lett. 83, 213 (2003)] indicated that filaments created in femtosecond high-power pulses propagating in air are surprisingly robust when interacting with microscopic water droplets. We present numerical modeling of the dynamics of the filament-droplet interaction. Our simulation results provide further insight into the interplay between the filament's core and the wide transverse pedestal of the pulse. It is shown that the robustness of the filament comes from the transverse low-intensity pedestal that controls the formation of the central hot spot. Implications for penetration of wide, high-power beams through obscurants are discussed. © 2004 Optical Society of America.
• Kolesik, M., & Moloney, J. V. (2004). Self-healing femtosecond light filaments. Optics letters, 29(6), 590--592.
• Kolesik, M., Wright, E., & Moloney, J. (2004). Dynamic nonlinear X waves for femtosecond pulse propagation in water. Physical review letters, 92(25), 253901.
• Kolesik, M., Wright, E., & Moloney, J. (2004). Simulation of femtosecond pulse propagation in sub-micron diameter tapered fibers. Applied Physics B, 79(3), 293--300.
• Kouznetsov, D., & Moloney, J. V. (2004). Boundary behaviour of modes of a Dirichlet Laplacian. Journal of Modern Optics, 51(13), 1955-1962.
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  Abstract: The problem of uncoupled modes of the pump in a double-clad fibre amplifier is analysed. As long as such modes avoid the core of the fibre, we consider the Dirichlet Laplacian problem which neglects the core. In this approach, the boundary of the cladding is treated as an ideal mirror. The laws of conservation established for the paraxial equation of diffraction give certain integral relations for the derivatives of modes at the boundary. Such relations are formulated as theorems. These theorems show ways to non-traditional design of single-mode fibre amplifiers with a multimode pump. In particular, the conservation of momentum can be applied to the design of the slab-pumped fibre amplifier. The conservation of angular momentum predicts high efficiency of coupling of a pump into a doped core embedded in a spiral-shaped double-clad fibre. Such predictions agree with results of numerical experiments published recently and allow a geometric optics interpretation.
• Kouznetsov, D., & Moloney, J. V. (2004). Boundary behaviour of modes of a Dirichlet Laplacian. journal of modern optics, 51(13), 1955--1962.
• Kouznetsov, D., & Moloney, J. V. (2004). Slab delivery of incoherent pump light to double-clad fiber amplifiers: An analytic approach. IEEE Journal of Quantum Electronics, 40(4), 378-383.
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  Abstract: Delivery of incoherent diode bar pump power via a tapered slab into a double-clad fiber amplifier allows for compact and efficient devices. We provide analytic estimates of system parameters for robust slab coupled configurations.
• Kouznetsov, D., & Moloney, J. V. (2004). Slab delivery of incoherent pump light to double-clad fiber amplifiers: An analytic approach. IEEE journal of quantum electronics, 40(4), 378--383.
• Li, L., Morrell, M., Qiu, T., Temyanko, V. L., Schülzgen, A., Mafi, A., Kouznetsov, D., Moloney, J. V., Luo, T., Jiang, S., & Peyghambarian, N. (2004). Short cladding-pumped Er/Yb phosphate fiber laser with 1.5 W output power. Applied Physics Letters, 85(14), 2721-2723.
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  Abstract: The experimental results on a high-power, cladding-pumped, heavily Er/Yb co-doped phosphate fiber laser of very short length were presented. It was found that up to 1.5 W cw laser power was obtained from an 11-cm-long multimode-core active fiber with optimized input and output couplers when pumped by a 15 W diode laser at 975 nm. An IC with high reflectivity at 1.5 μm was fabricated which exhibited high transmission at 975 nm. Analysis shows that the IC and OC were optimized and a slope efficiency of 10% was demonstrated against the launched pump power.
• Li, L., Morrell, M., Qiu, T., Temyanko, V., Schulzgen, A., Mafi, A., Kouznetsov, D., Moloney, J., Luo, T., Jiang, S., & others, . (2004). Short cladding-pumped Er/Yb phosphate fiber laser with 1.5 W output power. Applied physics letters, 85(14), 2721--2723.
• Liu, T., Zakharian, A. R., Fallahi, M., Moloney, J. V., & Mansuripur, M. (2004). Multimode interference-based photonic crystal waveguide power splitter. Journal of Lightwave Technology, 22(12), 2842-2846.
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  Abstract: A compact power splitter based on the multimode interference (MMI) effect in photonic crystal waveguides is designed and analyzed. The device size reduction compared with the conventional MMI power splitter can be attributed to the large dispersion of the photonic crystal waveguides. The Massachusetts Institute of Technology Photonic-Bands code is used to calculate the band structures of photonic crystal waveguides. The finite-difference time-domain method is adopted to simulate the relevant structures. © 2004 IEEE.
• Liu, T., Zakharian, A. R., Fallahi, M., Moloney, J. V., & Mansuripur, M. (2004). Multimode interference-based photonic crystal waveguide power splitter. Journal of lightwave technology, 22(12), 2842.
• Mafi, A., & Moloney, J. V. (2004). Phase locking in a passive multicore photonic crystal fiber. JOSA B, 21(5), 897--902.
• Mafi, A., & Moloney, J. V. (2004). Phase locking in a passive multicore photonic crystal fiber. Journal of the Optical Society of America B: Optical Physics, 21(5), 897-902.
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  Abstract: We investigate the possibility of phase locking in a multicore photonic crystal fiber. We analyze the modal behavior of photonic crystal fibers with two and six cores and compare them with the usual single-core case. We also show how the strength of the coupling among modes belonging to different cores can be controlled by adjusting the size of the airholes between the waveguiding cores. We then analyze the Talbot effect in the case of the six-core photonic crystal as a pseudoperiodic structure and show that there exists the possibility of using a Talbot resonator to achieve phase locking in multicore photonic crystal fibers. © 2004 Optical Society of America.
• Mafi, A., Moloney, J. V., Kouznetsov, D., Schulzgen, A., Jiang, S., Luo, T., & Peyghambarian, N. (2004). A large-core compact high-power single-mode photonic crystal fiber laser. Photonics Technology Letters, IEEE, 16(12), 2595--2597.
• Mafi, A., Moloney, J. V., Kouznetsov, D., Schülzgen, A., Jiang, S., Luo, T., & Peyghambarian, N. (2004). A large-core compact high-power single-mode photonic crystal fiber laser. IEEE Photonics Technology Letters, 16(12), 2595-2597.
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  Abstract: A novel method for making a compact high-power single-mode photonic crystal fiber laser (PCFL) is proposed. The entire photonic crystal fiber is doped uniformly with active material yet only the core is pumped. Numerical simulations predict that, by using Er-Yb codoped phosphate glass, it is possible to extract 9.5 W from a 1.8-cm-long PCFL with a 100-μm core diameter pumped with 20 W, achieving near 50% efficiency. © 2004 IEEE.
• Mansuripur, M., Zakharian, A. R., & Moloney, J. V. (2004). Transmission of Light Through Small Elliptical Apertures (Part 2). Optics and Photonics News, 15(4), 44-48.
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  Abstract: The transmission of light through small elliptical apertures in a thin silver film at λ=1.0 μm was analyzed. Both cases of incident polarization parallel and perpendicular to the major axis of the ellipse were considered. The transmission efficiency ,η, was found to be low for parallel polarization and high for perpendicular polarization. It was also found that for the elliptical hole under low transmission conditions, η dropped rapidly with an increasing film thickness.
• Mansuripur, M., Zakharian, A. R., & Moloney, J. V. (2004). Transmission of light through small elliptical apertures (Part 1). Optics and Photonics News, 15(3), 38-43.
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  Abstract: An overview is given of the results of computer simulations based on the Finite Difference Time Domain (FDTD) method for an elliptical aperture in a thin metal film illuminated by a normally incident, monochromatic plane wave. Both cases of incident polarization parallel and perpendicular to the long axis of the ellipses are considered.
• Mansuripur, M., Zakharian, A. R., & Moloney, J. V. (2004). Transmission of light through small elliptical apertures (Part 2). Optics and photonics news, 15(4), 44--48.
• Matus, M., Kolesik, M., Moloney, J. V., Hofmann, M., & Koch, S. W. (2004). Dynamics of two-color laser systems with spectrally filtered feedback. JOSA B, 21(10), 1758--1771.
• Matus, M., Kolesik, M., Moloney, J. V., Hofmann, M., & Koch, S. W. (2004). Dynamics of two-color laser systems with spectrally filtered feedback. Journal of the Optical Society of America B: Optical Physics, 21(10), 1758-1771.
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  Abstract: Two-color laser systems based on a semiconductor laser device and spectrally filtered feedback are studied. By use of a broadband numerical simulator and realistic active-structure optical responses, various two-color lasing configurations are investigated. Five characteristic dynamic regimes are observed and classified as semicoherent, coherent, multimode, chaotic, and multimode chaotic. Practical implications for gigahertz or terahertz signal-generation applications are discussed. © 2004 Optical Society of America.
• Moloney, J., Kolesik, M., & Matus, M. (2004). Dynamics of two-color laser systems with spectrally filtered feedback. Journal of the Optical Society of America B, Optical physic, 1758--1771.
• Peyghambarian, N., Qiu, T., Polynkin, P., Sch\"ulzgen, A., Li, L., Temyanko, V., Mansuripur, M., & Moloney, J. V. (2004). Short fiber lasers produce record power/length of 1.33 W/cm. Opt. \& Photon. News, 15, 12--41.
• Peyghambarian, N., Qiu, T., Polynkin, P., Schulzgen, A., Li, L. i., Temyanko, V., Mansuripur, M., & Moloney, J. V. (2004). Short fiber lasers produce record power/length of 1.33W/cm. Optics and Photonics News, 15(12), 41-.
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  Abstract: The experimental results achieved with short (7cm) phosphate fiber lasers which generate more than 9.3 W multimode and 4 W single mode output power were presented. The power generated per unit fiber length of 1.33W/cm represents a record in the fiber laser. The development of on-chip, watt-level single-frequency light sources in the 1,550 nm wavelength band. The maximum output power of a centimeters long laser was limited for the most part to the milliwatt level because of the difficulty of increasing ion doping concentrations in the fibers and of achieving high pump absorption with a double-cladding pump. A new side-pumping scheme compatible with short fiber lasers was demonstrated. The side-pumped laser constitutes a 12 cm long circular fiber.
• Qiu, T., Li, L., Schulzgen, A., Temyanko, V., Luo, T., Jiang, S., Mafi, A., Moloney, J., & Peyghambarian, N. (2004). Generation of 9.3-W multimode and 4-W single-mode output from 7-cm short fiber lasers. Photonics Technology Letters, IEEE, 16(12), 2592--2594.
• Qiu, T., Li, L., Schülzgen, A., Temyanko, V. L., Luo, T., Jiang, S., Mafi, A., Moloney, J. V., & Peyghambarian, N. (2004). Generation of 9.3-W multimode and 4-W single-mode output from 7-cm short fiber lasers. IEEE Photonics Technology Letters, 16(12), 2592-2594.
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  Abstract: We generate 9.3-W continuous-wave 1535-nm multimode output from a 7.0-cm short-length Er-Yb codoped phosphate fiber laser. A slope efficiency of 29% is obtained at pump powers below 27 W. Very high output power per unit fiber length of 1.33 W/cm is achieved. From another 7.1-cm Er-Yb codoped fiber laser, 4.0-W single-transverse-mode output with M 2 ≈ 1.1 is generated. © 2004 IEEE.
• Thr\"anhardt, A., Becker, S., Schlichenmaier, C., Kuznetsova, I., Meier, T., Koch, S., Hader, J., Moloney, J., & Chow, W. (2004). Nonequilibrium gain in optically pumped GaInNAs laser structures. Applied physics letters, 85, 5526.
• Thränhardt, A., Becker, S., Schlichenmaier, C., Kuznetsova, I., Meier, T., Koch, S. W., Hader, J., Moloney, J. V., & Chow, W. W. (2004). Nonequilibrium gain in optically pumped GalnNAs laser structures. Applied Physics Letters, 85(23), 5526-5528.
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  Abstract: A theory is presented which couples a dynamical laser model to a fully microscopic calculation of scattering effects. Calculations for two optically pumped GalnNAs laser structures show how this approach can be used to analyze nonequilibrium and dynamical laser properties over a wide range of system parameters. © 2004 American Institute of Physics.
• Webb, G., S\orensen, M. P., Brio, M., Zakharian, A. R., & Moloney, J. V. (2004). Variational principles, Lie point symmetries, and similarity solutions of the vector Maxwell equations in non-linear optics. Physica D: Nonlinear Phenomena, 191(1), 49--80.
• Xie, Y., Zakharian, A. R., Moloney, J. V., & Mansuripur, M. (2004). Transmission of light through slit apertures in metallic films. Optics Express, 12(25), 6106-6121.
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  PMID: 19488253;Abstract: Transmission of polarized light through sub-wavelength slit apertures is studied based on the electromagnetic field distributions obtained in computer simulations. The results show the existence of a cutoff for E|| and a strong transmission (with no cutoff) for E⊥ here || and ⊥ refer to the direction of the incident E-field relative to the long axis of the slit. These observations are explained by the standard waveguide theory involving inhomogeneous plane waves that bounce back and forth between the interior walls of the slit aperture. We examine the roles played by the slit-width, by the film thickness, and by the real and imaginary parts of the host material's dielectric constant in determining the transmission efficiency. We also show that the slit's sharp edges can be rounded to eliminate highly-localized electric dipoles without significantly affecting the slit's throughput. Finally, interference among the surface charges and currents induced in the vicinity of two adjacent slits is shown to result in enhanced transmission through both slits when the slits are separated by about one half of one wavelength. © 2004 Optical Society of America.
• Xie, Y., Zakharian, A., Moloney, J., & Mansuripur, M. (2004). Transmission of light through slit apertures in metallic films. Optics Express, 12(25), 6106--6121.
• Zakharian, A. R., Mansuripur, M., & Moloney, J. V. (2004). Transmission of light through small elliptical apertures. Optics Express, 12(12), 2631-2648.
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  PMID: 19475104;Abstract: The results of computer simulations based on the Finite Difference Time Domain method with local space and time grid refinement, are presented for an elliptical aperture in a thin metal film illuminated by a normally incident, monochromatic plane wave. Both cases of incident polarization parallel and perpendicular to the long axis of the ellipse are considered. An intuitive description of the behavior of the electromagnetic fields is developed in each case, and simulation results that exhibit patterns similar to those expected from this qualitative analysis are presented. The simulations reveal, in quantitative detail, the amplitude and phase behavior of the E- and B-fields in and around the aperture. © 2004 Optical Society of America.
• Zakharian, A., Brio, M., Moloney, J., & others, . (2004). FDTD based second-order accurate local mesh refinement method for Maxwell's equations in two space dimensions. Communications in Mathematical Sciences, 2(3), 497--513.
• Hader, J., Koch, S. W., & Moloney, J. V. (2003). Microscopic theory of gain and spontaneous emission in GaInNAs laser material. Solid-State Electronics, 47(3), 513-521.
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  Abstract: A fully microscopic model is used to calculate absorption/gain and spontaneous emission for GaInNAs quantum-well laser gain media. It is demonstrated how this approach can be used to derive the optical properties for the regime of semiconductor laser operation from low density photo luminescence spectra which can be obtained from simple experiments. Numerical results are presented showing that increased well depth leads to strongly increased differential gains and gain amplitudes and pronounced shifts of the gain maximum with increasing density. On the basis of a quantum Blotzmann model for the incoherent carrier dynamics it is shown, that high carrier confinement can lead to unusually long carrier capture times. Furthermore, temperature dependent bandstructure parameters for GaInNAs for the applied 10-band k·p-model are presented that have been derived from comparison to recent experimental data. © 2002 Elsevier Science Ltd. All rights reserved.
• Hader, J., Koch, S., & Moloney, J. (2003). Microscopic theory of gain and spontaneous emission in GaInNAs laser material. Solid-State Electronics, 47(3), 513--521.
• Hader, J., Moloney, J. V., Koch, S. W., & Chow, W. W. (2003). Microscopic Modeling of Gain and Luminescence in Semiconductor. IEEE Journal on Selected Topics in Quantum Electronics, 9(3), 688-697.
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  Abstract: The capabilities of a fully microscopic approach for the calculation of optical material properties of semiconductor lasers are reviewed. Several comparisons between the results of these calculations and measured data are used to demonstrate that the approach yields excellent quantitative agreement with the experiment. It is outlined how this approach allows one to predict the optical properties of devices under high-power operating conditions based only on low-intensity photo luminescence (PL) spectra. Examples for the gain-, absorption-, PL- and linewidth enhancement factor-spectra in single and multiple quantum-well structures, superlattices, Type II quantum wells and quantum dots, and for various material systems are discussed.
• Hader, J., Moloney, J. V., Koch, S. W., & Chow, W. W. (2003). Microscopic modeling of gain and luminescence in semiconductors. Selected Topics in Quantum Electronics, IEEE Journal of, 9(3), 688--697.
• Kolesik, M., Katona, G., Moloney, J., & Wright, E. (2003). Nonlinear Dynamics, Fluid Dynamics, Classical Optics, etc.-Physical Factors Limiting the Spectral Extent and Band Gap Dependence of Supercontinuum Generation. Physical Review Letters, 91(4), 43905--44100.
• Kolesik, M., Katona, G., Moloney, J., & Wright, E. (2003). Physical factors limiting the spectral extent and band gap dependence of supercontinuum generation. Physical review letters, 91(4), 043905.
• Kolesik, M., Katona, G., Moloney, J., & Wright, E. (2003). Theory and simulation of supercontinuum generation in transparent bulk media. Applied Physics B, 77(2-3), 185--195.
• Kolesik, M., Matus, M., & Moloney, J. (2003). All-optical Mach-Zehnder-Interferometer-based demultiplexer-a computer simulation study. Photonics Technology Letters, IEEE, 15(1), 78--80.
• Kolesik, M., Matus, M., & Moloney, J. V. (2003). All-optical Mach-Zehnder-interferometer-based demultiplexer - A computer simulation study. IEEE Photonics Technology Letters, 15(1), 78-80.
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  Abstract: An all-optical demultiplexer based on a Mach-Zehnder interferometer (MZI) is simulated using a realistic simulation engine. A novel scheme is proposed that utilizes the active interferometer arms in a bidirectional regime for simultaneous pre-amplification of the control light pulses and for differential nonlinear control of the interferometer balance. The device design incorporates an on-chip delay line as well as fine-tuning of the control pulse powers for optimal extinction ratio. This leads to a more compact device and an improved performance at speeds of up to 200 Gb/s.
• Kouznetsov, D., & Moloney, J. V. (2003). Highly Efficient, High-Gain, Short-Length, and Power-Scalable Incoherent Diode Slab-Pumped Fiber Amplifier/Laser. IEEE Journal of Quantum Electronics, 39(11), 1452-1461.
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  Abstract: We propose a new geometry of a clad-pumped fiber amplifier/laser that includes at least one doped core which guides the signal wave and at least one clad region that guides the incoherent pump. Our proposed geometry enables the incoherent diode pump light to be efficiently absorbed by the doped glass core over very short lengths on the order of a few to tens of centimeters. The transparent cladding is realized as a narrow slab with refractive index higher than that of the core. The slab is designed to effectively capture all of the incoherent pump light and is tapered to force the highly moded incoherent guided light into the strongly absorbing core. Modes of this composite waveguide structure are analyzed in this paper. Criteria are established in terms of the refractive indices of the core, slab, and cladding that ensure efficient absorption of the pump light in the core while ensuring that only a single or few lowest order signal modes can propagate in the amplifying core. Numerical simulations with the beam propagation method and a modal expansion technique confirm that a significant enhancement of the absorption efficiency of the pump in the core can be realized by tapering the slab waveguide. Assuming a local absorption rate of 10 m-1 of the intensity of the pump in a core of radius 4.3 μm and a realistic multimode diode pump distributed over a 100-μm aperture, an absorption efficiency of 94% can be realized over an amplifier length of 2 cm. The geometry is scalable to longer lengths and multiple incoherent diode-pumped slab claddings.
• Kouznetsov, D., & Moloney, J. V. (2003). Highly efficient, high-gain, short-length, and power-scalable incoherent diode slab-pumped fiber amplifier/laser. Quantum Electronics, IEEE Journal of, 39(11), 1452--1461.
• Kouznetsov, D., & Moloney, J. V. (2003). Novel slab-pumped, high-power, glass amplifiers and lasers. Frontiers in Optics. doi:10.1364/fio.2003.mt79
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  We will discuss novel slab wave guide coupler designs that allow for efficient incoherent diode pump light absorption in highly-doped, high gain, short length fiber amplifiers and lasers. In contrast to end pumping, the pump light is absorbed uniformly along the active material thereby avoiding problems associated with spatial hole-burning during laser operation.
• Mafi, A., Moloney, J. V., & Gundu, K. M. (2003). Design and modeling of compact high power fiber lasers. Frontiers in Optics. doi:10.1364/fio.2003.mt69
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  Highly-doped phosphate glasses provide significantly higher gain than regular silica doped glasses. We will discuss a novel design strategy for compact, high gain, double clad and photonic crystal fiber lasers and amplifiers. Modeling tools include higher order finite element-based vector modal solvers for passive and active single and multi-core devices, optical and thermal transport and mechanical stress calculations for high power laser operation.
• Mansuripur, M., Zakharian, A. R., & Moloney, J. V. (2003). Interaction of Light with Subwavelength Structures. Optics and Photonics News, 14(3), 56-61.
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  Abstract: The interaction of light with subwavelength structures is studied. The application of the finite difference time domain (FDTD) method to solve the problems involving the interaction between a focussed beam of light and the subwavelength structures is also discussed. The simulation results are presented for the case of a focussed beam interacting with small pits and apertures in a thin film supported by a transparent substrate.
• Mansuripur, M., Zakharian, A. R., & Moloney, J. V. (2003). The interaction of light with subwavelength structures. Optics and photonics news, 14(3), 56--61.
• Matus, M., Moloney, J. V., & Kolesik, M. (2003). Relevance of symmetry for the synchronization of chaotic optical systems and the related Lang-Kobayashi model limitations. Physical Review E - Statistical, Nonlinear, and Soft Matter Physics, 67(1 2), 162081-1620820.
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  Abstract: Synchronization of chaotic semiconductor lasers was discussed. Coupling methods which includes configurations where transmitter laser system is itself chaotic and drives a receiver system were used. Results showed the relevance of symmetry for the synchronization which was achieved between two identical lasers.
• Matus, M., Moloney, J., & Kolesik, M. (2003). Relevance of symmetry for the synchronization of chaotic optical systems and the related Lang-Kobayashi model limitations. Physical Review E, 67(1), 016208.
• White, J. K., & Moloney, J. V. (2003). A Coupled-Mode Model for the Fabry-Perot Semiconductor Laser Kink Instability. IEEE Journal on Selected Topics in Quantum Electronics, 9(3), 816-822.
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  Abstract: This paper derives a coupled-mode Fabry-Perot semiconductor laser model from the longitudinal-mode laser rate equations with parabolic gain dispersion. Truncating the full coupled-mode model permits stability analysis of the Fabry-Perot laser kink instability, which is a mode hop with increasing current. Two mechanisms contribute to the mode hop: The Silberberg-Bar-Joseph instability transports energy from higher frequencies to lower frequencies and gain dispersion stops the energy transport. Numerical simulations have shown that higher order carrier modes are excited during intervals of energy transport among the optical modes. These numerical results suggest that modes greatly detuned from the peak gain affect the laser dynamics.
• White, J., & Moloney, J. (2003). A coupled-mode model for the Fabry-Perot semiconductor laser kink instability. Selected Topics in Quantum Electronics, IEEE Journal of, 9(3), 816--822.
• Zakharian, A. R., Hader, J., Moloney, J. V., Koch, S. W., Brick, P., & Lutgen, S. (2003). Experimental and theoretical analysis of optically pumped semiconductor disk lasers. Applied Physics Letters, 83(7), 1313-1315.
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  Abstract: The power scaling of optically pumped semiconductor (OPS)-disk lasers was experimentally demonstrated by minimizing the thermal resistance between active region and heat sink. The dependence of the computed output power on the substrate thickness and detuning was discussed. The results showed the crucial thermal management in such devices for high efficiency and high-power OPS-disk lasers with brilliant beam quality.
• Zakharian, A. R., Moloney, J. V., & Mansuripur, M. (2003). Simulating near-field effects in high-density optical-disk data storage. Computing in Science \& Engineering, 5(6), 15--21.
• Zakharian, A. R., Moloney, J. V., & Mansuripur, M. (2003). Simulating near-field effects in high-density optical-disk data storage. Computing in Science and Engineering, 5(6), 15-21.
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  Abstract: The simulation of near-field effects in high density optical disk data storage is discussed. Plane wave expansion methods for classical diffraction theory equations, coupled with the direct numerical solution of Maxwell's equations were used for simulation. Finite difference time domain (FDTD) methods based on the local grid refinement approach allowed improved computational efficiency for simulations.
• Zakharian, A., Hader, J., Moloney, J., Koch, S., Brick, P., & Lutgen, S. (2003). Experimental and theoretical analysis of optically pumped semiconductor disk lasers. Applied physics letters, 83(7), 1313--1315.
• Breede, M., Hoffmann, S., Zimmermann, J., Struckmeier, J., Hofmann, M., Kleine-Ostmann, T., Knobloch, P., Koch, M., Meyn, J. P., Matus, M., Koch, S. W., & Moloney, J. V. (2002). Fourier-transform external cavity lasers. Optics Communications, 207(1-6), 261-271.
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  Abstract: We explore the potential of a new laser resonator design that uses an intracavity Fourier transformation and allows for multi-color operation, gain extension and intracavity second harmonic generation (SHG). First, purely electronically controlled wavelength tuning is demonstrated using liquid crystal displays (LCDs) and digital mirror devices. Moreover, the new design can be applied to different lasers as shown on the examples of a laser diode and a Thulium-doped fiber laser in the mid-infrared. Furthermore, we demonstrate the simultaneous control of multiple gain media within one single external cavity. In addition, tunable emission in the 490 nm range is obtained using intracavity SHG with one single control parameter. Finally, we unambiguously prove simultaneous multi-wavelength operation with variable wavelength spacings and apply it to the generation of THz difference frequencies. © 2002 Elsevier Science B.V. All rights reserved.
• Breede, M., Hoffmann, S., Zimmermann, J., Struckmeier, J., Hofmann, M., Kleine-Ostmann, T., Knobloch, P., Koch, M., Meyn, J., Matus, M., & others, . (2002). Fourier-transform external cavity lasers. Optics communications, 207(1), 261--271.
• Hader, J., Zakharian, A. R., Moloney, J. V., Nelson, T. R., Siskaninetz, W. J., Ehret, J. E., Hantke, K., Hofmann, M., & Koch, S. W. (2002). Quantitative prediction of semiconductor laser characteristics based on low intensity photoluminescence measurements. IEEE Photonics Technology Letters, 14(6), 762-764.
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  Abstract: A general scheme for the determination of vital operating characteristics of semiconductor lasers from low intensity photo-luminescence spectra is outlined and demonstrated.
• Hader, J., Zakharian, A. R., Moloney, J. V., Nelson, T. R., Siskaninetz, W. J., Ehret, J. E., Hantke, K., Koch, S. W., & Hofmann, M. R. (2002). Laser materials: Semiconductor quantum-well designer active materials. Optics & Photonics News, 13(12), 22-22. doi:10.1364/opn.13.12.000022
• Hader, J., Zakharian, A., Moloney, J., Nelson, T., Siskaninetz, W., Ehret, J., Hantke, K., Hofmann, M., & Koch, S. (2002). Quantitative prediction of semiconductor laser characteristics based on low intensity photoluminescence measurements. Photonics Technology Letters, IEEE, 14(6), 762--764.
• Hofmann, M. R., Gerhardt, N., Wagner, A. M., Ellmers, C., Hohnsdorf, F., Koch, J., Stolz, W., Koch, S. W., Ruhle, W., Hader, J., & others, . (2002). Emission dynamics and optical gain of 1.3-$\mu$m (GaIn)(NAs)/GaAs lasers. Quantum Electronics, IEEE Journal of, 38(2), 213--221.
• Hofmann, M. R., Gerhardt, N., Wagner, A. M., Ellmers, C., Höhnsdorf, F., Koch, J., Stolz, W., Koch, S. W., Rühle, W. W., Hader, J., Moloney, J. V., O'Reilly, E., Borchert, B., Egorov, A. Y., Riechert, H., Schneider, H. C., & Chow, W. W. (2002). Emission dynamics and optical gain of 1.3-μm (GaIn)(NAs)/GaAs lasers. IEEE Journal of Quantum Electronics, 38(2), 213-221.
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  Abstract: The ultrafast emission dynamics of a 1.3-μm (GaIn)(NAs)/GaAs vertical-cavity surface-emitting laser is studied by femtosecond luminescence upconversion. We obtain a minimum peak delay of 15.5 ps and a minimum pulse width of 10.5 ps. Laser operation with picosecond emission dynamics is demonstrated over a temperature range from 30 to 388 K. The bandgap shift with temperature of (GaIn)(NAs)/GaAs is determined to be about -2.9 · 10-4 eV/K, which is smaller than for GaAs. Our measurements of the optical gain provide gain spectra similar to those of commercial (GaIn)(PAs)/InP - structures at moderate densities but broaden considerably for elevated carrier densities due to the stronger carrier confinement. We compare our experimental results with gain spectra calculated from a microscopic model and confirm the predictive capability of the model. The theoretical gain spectra are used as the input for a calculation of the temperature dependence of the (GaIn)(NAs)/GaAs surface-emitter emission which results in very good agreement with experiment.
• Klar, P. J., Grüning, H., Heimbrodt, W., Weiser, G., Koch, J., Volz, K., Stolz, W., Koch, S. W., Tomic, S., Choulis, S. A., Hosea, T. J., O'Reilly, E., Hofmann, M., Hader, J., & Moloney, J. V. (2002). Interband transitions of quantum wells and device structures containing Ga(N, As) and (Ga, In)(N, As). Semiconductor Science and Technology, 17(8), 830-842.
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  Abstract: The unusual N-induced band formation and band structure of Ga(N, As) and (Ga, In)(N, As) alloys are also reflected in the electronic structure of quantum wells (QWS) and device structures containing these non-amalgamation-type alloys. This review is divided into three parts. The first part deals with band structure aspects of bulk Ga(N, As) and motivates the possibility of a k·p-like parameterization of the band structure in terms of the level repulsion model between the conduction band edge of the host and a localized N-level. The second part presents experimental studies of interband transitions in Ga(N, As)/GaAs and (Ga, In)(N, As)/GaAs QW structures addressing band offsets, electron effective mass changes and an intrinsic mechanism contributing to the blueshift of the (Ga, In)(N, As) band gap on annealing. The observed interband transitions can be well described using a ten-band k·p model based on the level repulsion scheme. The third part deals with (Ga, In)(N, As)-based laser devices. The electronic structure of the active region of vertical-cavity surface-emitting laser and edge-emitter laser structures is studied by modulation spectroscopy. The gain of such structures is measured by optical methods and analysed in terms of a model combining the ten-band k·p description of the band structure and generalized Bloch equations.
• Klar, P., Gr\"uning, H., Heimbrodt, W., Weiser, G., Koch, J., Volz, K., Stolz, W., Koch, S., Tomi\'c, S., Choulis, S., & others, . (2002). Interband transitions of quantum wells and device structures containing Ga (N, As) and (Ga, In)(N, As). Semiconductor science and technology, 17(8), 830.
• Kolesik, M., Moloney, J. V., & Mlejnek, M. (2002). Unidirectional optical pulse propagation equation. Physical Review Letters, 89(28 I), 283902/1-283902/4.
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  Abstract: A robust unidirectional nonlinear pulse propagation equation was derived. The resultant equation provides a seamless transition between a full vector Maxwell and various envelope approaches discussed in a previous study. It was shown that the UPPE model allows to establish the validity of various approximations inherent in various envelope approaches and investigate extreme nonlinear self-focusing of a femtosecond pulse.
• Kolesik, M., Moloney, J., & Mlejnek, M. (2002). Unidirectional optical pulse propagation equation. Physical review letters, 89(28), 283902.
• Kouznetsov, D., & Moloney, J. V. (2002). Efficiency of pump absorption in double-clad fiber amplifiers. II. Broken circular symmetry. JOSA B, 19(6), 1259--1263.
• Kouznetsov, D., & Moloney, J. V. (2002). Efficiency of pump absorption in double-clad fiber amplifiers. II. Broken circular symmetry. Journal of the Optical Society of America B: Optical Physics, 19(6), 1259-1263.
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  Abstract: Absorption of an incoherent pump in a double-clad fiber amplifier is analyzed in the paraxial wave approximation. Different inner cladding shapes are considered. A small spiral distortion of an otherwise circular inner cladding shape is shown to enhance the coupling efficiency significantly relative to other geometries. © 2002 Optical Society of America.
• Kouznetsov, D., & Moloney, J. V. (2002). Efficiency of pump absorption in double-clad fiber amplifiers. III. Calculation of modes. JOSA B, 19(6), 1304--1309.
• Kouznetsov, D., & Moloney, J. V. (2002). Efficiency of pump absorption in double-clad fiber amplifiers. III. Calculation of modes. Journal of the Optical Society of America B: Optical Physics, 19(6), 1304-1309.
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  Abstract: Using an analogy with quantum mechanics we employ a technique that enables us to calculate the efficiency of an incoherent pump in general-geometry double-clad fibers. This approach yields accurate estimates of the absorption rate of each mode of the pump in the first order of perturbation theory. Such estimates are compared with results of numerical simulations reported recently. The comparison confirms the high efficiency of a spiral-shaped cladding. © 2002 Optical Society of America.
• Mercier, J. -., & Moloney, J. V. (2002). Derivation of semiconductor laser mean-field and Swift-Hohenberg equations. Physical Review E - Statistical, Nonlinear, and Soft Matter Physics, 66(3), 036221/1-036221/19.
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  PMID: 12366238;Abstract: Bulk and quantum well semiconductor lasers by nature display fundamentally different physical characteristics relative to multilevel gas and solid state lasers. In particular, the refractive index is nonzero at peak gain and the peak gain can shift strongly with varying carrier density or temperature. Moreover, a quantum well laser gain may be strongly asymmetric if more than the lowest subband is populated. Rigorously computed and experimentally validated, gain and refractive index spectra are now available for a variety of quantum well structures emitting from the infrared to the visible. Active devices can be designed and grown such that the gain spectrum remains approximately parabolic for carrier density variations typically encountered in above threshold pumped broad area edge-emitting semiconductor lasers. Under this assumption, we derive a robust optical propagation model that tracks the important peak gain shifts and broadening as long as the gain remains approximately parabolic over the relevant energy range in a running laser. We next derive a multimode model where the longitudinal modes are projected out of the total field. The next stage is to derive a mean-field single longitudinal mode model for a wide aperture semiconductor laser. The mean-field model allows for significant cavity losses and widely different facet reflectivities such as occurs with antireflection- and high-reflectivity-coated facets. The single mode mean-field model is further reduced using an asymptotic expansion of the relevant physical fields with respect to a small parameter. The end result is a complex semiconductor Swift-Hohenberg description of a single longitudinal mode wide aperture laser. The latter should provide a useful model for studying scientifically and technologically important lasers such as vertical cavity surface emitting semiconductor lasers. © 2002 The American Physical Society.
• Mercier, J., & Moloney, J. (2002). Derivation of semiconductor laser mean-field and Swift-Hohenberg equations. Physical Review E, 66(3), 036221.
• Mirasso, C. R., Kolesik, M., Matus, M., White, J. K., & Moloney, J. V. (2002). Synchronization and multimode dynamics of mutually coupled semiconductor lasers. Physical Review A. Atomic, Molecular, and Optical Physics, 65(1), 138051-138054.
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  Abstract: A realistic laser simulation engine was used to study synchronization and multimode dynamics in mutually coupled semiconductor lasers. An injection current close to the threshold was used to pump the two lasers. The cross correlation function between longitudinal modes was computed to characterize degree of synchronization between different longitudinal modes of the two lasers. The quality of synchronization was found to depend on the bandwidth of the photodetector. Analysis suggested that synchronization was better for individual longitudinal modes than that for total intensity modes and extended over whole range of detection without losing its quality.
• S\orensen, M. P., Brio, M., Webb, G. M., & Moloney, J. V. (2002). Solitary waves, steepening and initial collapse in the Maxwell--Lorentz system. Physica D: Nonlinear Phenomena, 170(3), 287--303.
• White, J. K., Matus, M., & Moloney, J. V. (2002). Achronal generalized synchronization in mutually coupled semiconductor lasers. Physical Review E - Statistical, Nonlinear, and Soft Matter Physics, 65(3), 036229/1-036229/5.
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  Abstract: Heil et al. [Phys. Rev. Lett. 86, 795 (2001)] recently discovered achronal synchronization of chaos in mutually coupled semiconductor lasers. This paper offers an analytic interpretation of their experiment using a simple rate equation model. Local eigenvalue analysis shows that isochronal synchronization is unstable; achronal synchronization, on the other hand, is stable if a generalized synchronization function is introduced. Single- and multimode simulations have substantiated this rate equation interpretation. Finally, there is a brief examination of "chaos pass filtering." © 2002 The American Physical Society.
• White, J., Matus, M., & Moloney, J. (2002). Achronal generalized synchronization in mutually coupled semiconductor lasers. Physical Review E, 65(3), 036229.
• Cheng, C., Wright, E., & Moloney, J. (2001). Generation of electromagnetic pulses from plasma channels induced by femtosecond light strings. Physical review letters, 87(21), 213001.
• Hofmann, M., Wagner, A., Ellmers, C., Schlichenmeier, C., Sch\"afer, S., H\"ohnsdorf, F., Koch, J., Stolz, W., Koch, S., R\"uhle, W., & others, . (2001). Gain spectra of (GaIn)(NAs) laser diodes for the 1.3-$\mu$m-wavelength regime. Applied Physics Letters, 78(20), 3009--3011.
• Hofmann, M., Wagner, A., Ellmers, C., Schlichenmeier, C., Schäfer, S., Höhnsdorf, F., Koch, J., Stolz, W., Koch, S. W., Rühle, W., Hader, J., Moloney, J. V., O'Reilly, E., Borchert, B., Egorov, A., & Riechert, H. (2001). Gain spectra of (Galn)(NAs) laser diodes for the 1.3-μm-wavelength regime. Applied Physics Letters, 78(20), 3009-3011.
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  Abstract: Optical gain spectra of (Galn)(NAs)/GaAs quantum-well lasers operating in the 1.3-μm-emission-wavelength regime are measured and compared to those of a commercial (Galn)(AsP)/InP structure. Good agreement of the experimental results with computed spectra of a microscopic many-body theory is obtained. Due to the contributions of a second confined subband, a spectrally broad gain region is expected for (Galn)(NAs)/GaAs at elevated carrier densities. © 2001 American Institute of Physics.
• Kolesik, M., & Moloney, J. V. (2001). A spatial digital filter method for broad-band simulation of semiconductor lasers. IEEE Journal of Quantum Electronics, 37(7), 936-944.
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  Abstract: A novel method to simulate semiconductor lasers is presented that captures accurately the real and imaginary parts of the active medium response in a broad frequency range. It is a time-domain approach based on a spatial digital filter in the role of the optical field propagator. Careful treatment of numerical dispersion makes it possible to utilize effectively most of the available numerical bandwidth and obtain a realistic description of the laser dynamics.
• Kolesik, M., & Moloney, J. V. (2001). A spatial digital filter method for broad-band simulation of semiconductor lasers. Quantum Electronics, IEEE Journal of, 37(7), 936--944.
• Kolesik, M., Moloney, J., & Wright, E. (2001). Polarization dynamics of femtosecond pulses propagating in air. Physical Review E, 64(4), 046607.
• Kouznetsov, D., Moloney, J. V., & Wright, E. M. (2001). Efficiency of pump absorption in double-clad fiber amplifiers. I. Fiber with circular symmetry. JOSA B, 18(6), 743--749.
• Mirasso, C. R., Kolesik, M., Matus, M., White, J., & Moloney, J. V. (2001). Synchronization and multimode dynamics of mutually coupled semiconductor lasers. Physical Review A, 65(1), 013805.
• Mlejnek, M., Kolesik, M., Wright, E., & Moloney, J. (2001). Recurrent femtosecond pulse collapse in air due to plasma generation: numerical results. Mathematics and computers in simulation, 56(6), 563--570.
• Moloney, J. V. (2001). Light strings draw together. Physics World, 14(8), 28--28.
• Schjodt-Eriksen, J., Moloney, J., Wright, E., Feng, Q., & Christiansen, P. L. (2001). Polarization instability of femtosecond pulse splitting in normally dispersive self-focusing media. Optics letters, 26(2), 78--80.
• Zakharian, A. R., & Moloney, J. V. (2001). Comparison of contact designs for improved stability of broad area semiconductor lasers. IEEE Photonics Technology Letters, 13(12), 1280-1282.
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  Abstract: Patterned electrode designs are used to control optical mode shape in high-power semiconductor lasers by localizing current injection. In this letter, we present comparison of current density profiles in the active layer achieved by different contact designs. Single-voltage digitated contact, distributed regular and random Gaussian contact configurations are studied using numerical solutions of semiconductor device equations that govern electrostatic potential and carrier concentrations in three spatial dimensions. The results of our calculations indicate that lateral current profile is influenced by the contact shape in the transverse direction and the thickness of the junction on the contact side.
• Zakharian, A., & Moloney, J. (2001). Comparison of contact designs for improved stability of broad area semiconductor lasers. Photonics Technology Letters, IEEE, 13(12), 1280--1282.
• Burak, D., Moloney, J. V., & Binder, R. (2000). Macroscopic versus microscopic description of polarization properties of optically anisotropic vertical-cavity surface-emitting lasers. IEEE Journal of Quantum Electronics, 36(8), 956-970.
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  Abstract: A macroscopic model for optically anisotropic vertical-cavity surface-emitting lasers (VCSEL's) is derived from a microscopic model [Burak et al., Phys. Rev. A, vol. 61, pp. 53809-53830, 2000]. This provides a rigorous generalization of the phenomenological approaches to the description of polarization properties of VCSEL's used commonly in the literature. The optical anisotropy of the VCSEL structure is assumed to result from anisotropic strain of the active quantum-well material. The polarization-dependent linewidth enhancement factors and gain coefficients are calculated microscopically from the anisotropy of the valence bands. The influence of the anisotropic strain on the stability of polarization eigenmodes is investigated. A comparative study is performed between the full microscopic model and the macroscopic model on different levels of approximations. The results of the models agree very well for input/output characteristics of anisotropic VCSEL's. Also, the stability properties of polarization eigenmodes are qualitatively the same, although the ranges of stability are quantitatively different for both approaches. Incorporation of many-body effects into the analysis diminishes the agreement between microscopic and macroscopic theories.
• Burak, D., Moloney, J. V., & Binder, R. (2000). Microscopic theory of polarization properties of optically anisotropic vertical-cavity surface-emitting lasers. Physical Review A - Atomic, Molecular, and Optical Physics, 61(5), 538091-5380921.
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  Abstract: The polarization eigenmodes of vertical-cavity surface-emitting lasers (VCSELs) are investigated theoretically. The study is based on a first-principles theory and includes a microscopic model for the optically active quantum well and a vectorial solution of the VCSEL cavity mode problem. The theory is evaluated for an anisotropically strained GaAs quantum well structure, interacting with two orthogonally polarized VCSEL eigenmodes. The dependence of the calculated input-output characteristics and polarization stability criteria on microscopic input parameters such as the value of the strain are discussed for various levels of sophistication of the microscopic many-body effects used in the analysis. The results of the stability analysis are consistent with recent experimental observations of polarization switching, suggesting that anisotropic strain of the active quantum well may be a dominant factor in those observations.
• Burak, D., Moloney, J., & Binder, R. (2000). ARTICLES-Quantum optics, physics of lasers, nonlinear optics-Microscopic theory of polarization properties of optically anisotropic vertical-cavity surface-emitting lasers. Physical Review-Section A-Atomic Molecular and Optical Physics, 61(5), 53809--53809.
• Burak, D., Moloney, J., & Binder, R. (2000). Macroscopic versus microscopic description of polarization properties of optically anisotropic vertical-cavity surface-emitting lasers. Quantum Electronics, IEEE Journal of, 36(8), 956--970.
• Burak, D., Moloney, J., & Binder, R. (2000). Microscopic theory of polarization properties of optically anisotropic vertical-cavity surface-emitting lasers. Physical Review A, 61(5), 053809.
• Burak, D., Moloney, J., & Binder, R. (2000). PAPERS-Semiconductor Lasers and Amplifiers-Macroscopic versus Microscopic Description of Polarization Properties of Optically Anisotropic Vertical-Cavity Surface-Emitting Lasers. IEEE Journal of Quantum Electronics-Institute Electrical and Electronic Engineers, 36(8), 956--970.
• Diels, J., Rambo, P., Schwarz, J., Kolesik, M., Wright, E., & Moloney, J. (2000). Ultraviolet filamentation in air.
• Hader, J., Koch, S. W., Moloney, J. V., & O'Reilly, E. (2000). Gain in 1.3 μm materials: InGaNAs and InGaPAs semiconductor quantum-well lasers. Applied Physics Letters, 77(5), 630-632.
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  Abstract: The absorption and gain for an InGaNAs/GaAs quantum-well structure is calculated and compared to that of a more conventional InGaAs/InGaPAs structure, both lasing in the 1.3 μm range. Despite significant differences in the band structures, the gain value is comparable for high carrier densities in both structures and the transition energy at the gain maximum shows a similar blueshift with increasing carrier density. For low and intermediate carrier densities, the calculated gain in the InGaPAs system is significantly lower and the bandwidth smaller than in the InGaNAs system. © 2000 American Institute of Physics.
• Hader, J., Koch, S. W., Moloney, J. V., & O'Reilly, E. (2000). Influence of the valence-band offset on gain and absorption in GaNAs/GaAs quantum well lasers. Applied Physics Letters, 76(25), 3685-3687.
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  Abstract: The dependence of the gain and absorption in GaNAs/GaAs quantum well lasers on the valence-band offset is investigated. The calculated absorption strength, gain amplitudes, and gain bandwidth are found to depend crucially on the value of this offset. The shift of the peak gain transition energy with carrier density is shown to depend strongly on the magnitude of the offset, providing what should be a useful means to determine the offset experimentally. © 2000 American Institute of Physics.
• Hader, J., Koch, S., Moloney, J., & O’Reilly, E. (2000). Gain in 1.3 $\mu$m materials: InGaNAs and InGaPAs semiconductor quantum-well lasers. Applied Physics Letters, 77(5), 630--632.
• Hader, J., Koch, S., Moloney, J., & O’Reilly, E. (2000). Influence of the valence-band offset on gain and absorption in GaNAs/GaAs quantum well lasers. Applied Physics Letters, 76(25), 3685--3687.
• Kouznetsov, D., & Moloney, J. V. (2000). Novel slab-pumped, high-power, glass amplifiers and lasers..
• Luo, H., Kasunic, K. J., Macomber, S. H., Bedford, R., Moloney, J. V., & Fallahi, M. (2000). Tapered-cavity surface-emitting distributed-Bragg-reflector semiconductor lasers: modeling and experiment. IEEE Journal on Selected Topics in Quantum Electronics, 6(4), 594-600.
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  Abstract: We report on the design and fabrication of tapered cavity grating coupled surface-emitting distributed Bragg reflector (DBR) lasers in the 980-nm regime. A curved second-order grating is used at the end of a tapered gain section to provide feedback as well as collimated surface out-coupling. A detailed numerical analysis shows that operation up to approximately twice the threshold is possible without significant degradation of the far field. Near diffraction-limited collimated surface-emitting output with moderate power of about 150 mW is obtained under continuous operation.
• Luo, H., Kasunic, K., Macomber, S., Bedford, R., Moloney, J., & Fallahi, M. (2000). Tapered-cavity surface-emitting distributed-bragg-reflector semiconductor lasers: modeling and experiment. Selected Topics in Quantum Electronics, IEEE Journal of, 6(4), 594--600.
• Mafi, A., Gundu, K., & Moloney, J. V. (2000). Design and modeling of compact high power fiber lasers.
• Matus, M., Kolesik, M., & Moloney, J. V. (2000). Dynamics of a multi-color laser system based on filtered feedback.
• Moloney, J., Kolesik, M., Mlejnek, M., & Wright, E. (2000). Femtosecond self-guided atmospheric light strings. Chaos: An Interdisciplinary Journal of Nonlinear Science, 10(3), 559--569.
• Gilles, L., Moloney, J. V., & Vázquez, L. (1999). Electromagnetic shocks on the optical cycle of ultrashort pulses in triple-resonance Lorentz dielectric media with subfemtosecond nonlinear electronic Debye relaxation. Physical Review E - Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics, 60(1), 1051-1059.
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  PMID: 11969852;Abstract: The dynamical evolution of an intense ultrashort sub-10-fs two-cycle optical pulse is considered as it propagates through a transparent third-order dielectric medium characterized by three resonance lines and a finite sub-fs relaxation time of the electronic nonlinearity. Numerical integration of the full Maxwell's equations incorporating triple-resonance Lorentz linear dispersion and Debye nonlinear dispersion, for a linearly polarized electromagnetic pulse centered at λ0=1.24 μm in the normal dispersion region near the zero dispersion wavelength, shows the formation of shocks occurring on the optical cycle due to the generation of optical harmonics. The finite relaxation time of the nonlinear electronic response (sub-fs time scale) (i) slows down the steepening rate of the optical cycle; (ii) does not limit the generation of strongly phase matched optical harmonics, and consequently the development of infinitely sharp edges on the optical cycle producing its breaking when linear dispersion is not included; (iii) reduces the production of phase matched harmonics and consequently the sharpening of the jumps when dispersion is present, compared to the case of an instantaneous nonlinear response; and (iv) reduces the harmonic spectrum spreading and modulation at later times on the appearance of self-steepening of the electric field envelope. ©1999 The American Physical Society.
• Gilles, L., Moloney, J., & V\'azquez, L. (1999). Electromagnetic shocks on the optical cycle of ultrashort pulses in triple-resonance Lorentz dielectric media with subfemtosecond nonlinear electronic Debye relaxation. Physical Review E, 60(1), 1051.
• Hader, J., Bossert, D., Stohs, J., Chow, W. W., Koch, S. W., & Moloney, J. V. (1999). CLAMPING OF THE LINEWIDTH ENHANCEMENT FACTOR IN NARROW QUANTUM-WELL SEMICONDUCTOR LASERS. Applied Physics Letters, 74(16), 2277-2279. doi:10.1063/1.123823
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  The linewidth enhancement factor in single quantum-well GRINSCH semiconductor lasers is investigated theoretically and experimentally. For thin wells a small linewidth enhancement factor is obtained which clamps with increasing carrier density, in contrast to the monotonous increase observed for thicker wells. Microscopic many-body calculations reproduce the experimental observations attributing the clamping to a subtle interplay between excitation dependent gain shifts and carrier population distributions.
• Hader, J., Bossert, D., Stohs, J., Chow, W. W., Koch, S. W., & Moloney, J. V. (1999). Clamping of the linewidth enhancement factor in narrow quantum-well semiconductor lasers. Applied Physics Letters, 74(16), 2277-2279.
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  Abstract: The linewidth enhancement factor (LWEF) in single quantum-well lasers is analyzed theoretically and experimentally. The LWEF clamps with increasing carrier density and the correct LWEF at the gain peak is affected by the density dependence of the gain maximum. Calculations show that designing laser structures is possible, wherein the LWEF does not have to increase with increasing pump level.
• Hader, J., Bossert, D., Stohs, J., Chow, W., Koch, S., & Moloney, J. (1999). Clamping of the linewidth enhancement factor in narrow quantum-well semiconductor lasers. Applied physics letters, 74(16), 2277--2279.
• Hader, J., Moloney, J. V., & Koch, S. W. (1999). Microscopic theory of gain, absorption, and refractive index in semiconductor laser materials - influence of conduction-band nonparabolicity and Coulomb-induced intersubband coupling. IEEE Journal of Quantum Electronics, 35(12), 1878-1886.
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  Abstract: The influence of the conduction-band nonparabolicity and Coulomb coupling between different electronic subbands and different hole subbands on gain, absorption, and refractive index in semiconductor heterostructures is investigated. We implement these features into a fully microscopic approach. At low carrier densities, the nonparabolicity leads to a steeper increase of the absorption for increasing transition energy. In this regime, the Coulomb subband coupling allows for a shift of oscillator strength to energetically lower transitions. In the gain regime, the conduction-band nonparabolicity is shown to reduce the gain width for a given carrier density and to strongly modify the corresponding refractive index. The Coulomb coupling is especially important to determine the correct energetic position and density dependence of the gain maximum. In addition, it leads to a steeper transition from the gain to the absorptive region.
• Hader, J., Moloney, J., & Koch, S. (1999). Microscopic theory of gain, absorption, and refractive index in semiconductor laser materials-influence of conduction-band nonparabolicity and coulomb-induced intersubband coupling. Quantum Electronics, IEEE Journal of, 35(12), 1878--1886.
• Hader, J., Moloney, J., & Koch, S. (1999). PAPERS-Semiconductor Devices and Phenomena-Microscopic Theory of Gain, Absorption, and Refractive Index in Semiconductor Laser Materials--Influence of Conduction-Band Nonparabolicity and. IEEE Journal of Quantum Electronics-Institute Electrical and Electronic Engineers, 35(12), 1878--1886.
• Huyet, G., White, J. K., Kent, A. J., Hegarty, S. P., Moloney, J. V., & McInerney, J. G. (1999). Dynamics of a semiconductor laser with optical feedback. Physical Review A - Atomic, Molecular, and Optical Physics, 60(2), 1534-1537.
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  Abstract: A semiconductor laser with optical feedback is investigated based on its dynamics on the low-frequency fluctuation regime. It is shown that single and multimode operation of the laser can exhibit low-frequency fluctuations. Single-mode rate equations are used to describe fast dynamics analysis associated with low-frequency instability. Results revealed that every laser mode in the multimode regime show fast pulsation.
• Huyet, G., White, J., Kent, A., Hegarty, S., Moloney, J., & McInerney, J. (1999). Dynamics of a semiconductor laser with optical feedback. Physical Review A, 60(2), 1534.
• Mlejnek, M., Kolesik, M., Moloney, J., & Wright, E. (1999). Optically turbulent femtosecond light guide in air. Physical Review Letters, 83(15), 2938.
• Mlejnek, M., Wright, E. M., & Moloney, J. V. (1999). Moving-focus versus self-waveguiding model for long-distance propagation of femtosecond pulses in air. Quantum Electronics, IEEE Journal of, 35(12), 1771--1776.
• Mlejnek, M., Wright, E., & Moloney, J. (1999). Power dependence of dynamic spatial replenishment of femtosecond pulses propagating in air. Optics express, 4(7), 223--228.
• Mlejnek, M., Wright, E., Moloney, J., & Bloembergen, N. (1999). Second harmonic generation of femtosecond pulses at the boundary of a nonlinear dielectric. Physical review letters, 83(15), 2934.
• Moloney, J. V. (1999). Spontaneous generation of patterns and their control in nonlinear optical systems. Journal of Optics B: Quantum and Semiclassical Optics, 1(6), 183-190.
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  Abstract: The recent wealth of experimental observations of patterns in a variety of nonlinear optical systems has stimulated rapid growth in this area of nonlinear science. In this paper, we will review some of our old results on pattern formation in passive bistable resonators as a backdrop to discussing recent results on controlling patterns in high-power wide-aperture semiconductor lasers. As an illustration of the latter, a novel robust spatial/spectral filtering delay-feedback control scheme will be described which stabilizes and steers the weakly turbulent output of a broad area semiconductor laser. © 1999 IOP Publishing Ltd.
• Moloney, J., Indik, R., Hader, J., & Koch, S. (1999). Modeling semiconductor amplifiers and lasers: from microscopic physics to device simulation. JOSA B, 16(11), 2023--2029.
• Moloney, J., Indik, R., Hader, J., & Koch, S. (1999). SPATIAL AND POLARIZATION DYNAMICS OF SEMICONDUCTOR LASERS-Transverse-Mode Dynamics In Edge-Emitting Lasers-Modeling semiconductor amplifiers and lasers: From microscopic physics to device. Journal of the Optical Society of America-B-Optical Physics, 16(11), 2023--2029.
• White, J. K., & Moloney, J. V. (1999). Multichannel communication using an infinite dimensional spatiotemporal chaotic system. Physical Review A - Atomic, Molecular, and Optical Physics, 59(3), 2422-2426.
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  Abstract: Chaotic spatiotemporal dynamics generated by a nonlinear set of coupled partial differential equations are synchronized via a scalar complex variable. Our results show that synchronization is robust to noise, and we demonstrate chaotic communication in a high-dimensional system. We have also discovered that the added dimensionality creates a new quasisynchronous state, enabling the transmission of multiple messages through a single scalar complex channel. The feasibility of these novel ideas is demonstrated on a realistic numerical model of chaotic semiconductor lasers. © 1999 The American Physical Society.
• White, J., & Moloney, J. (1999). Multichannel communication using an infinite dimensional spatiotemporal chaotic system. Physical Review A, 59(3), 2422.
• Egan, A., Ning, C., Moloney, J., Indik, R., Wright, M., Bossert, D., & McInerney, J. (1998). Dynamic instabilities in master oscillator power amplifier semiconductor lasers. IEEE journal of quantum electronics, 34(1), 166--170.
• Faccio, D., Cacciatori, S., Gorini, V., Sala, V., Averchi, A., Lotti, A., Kolesik, M., & Moloney, J. (1998). Exporter cette r\'ef\'erence. Europhys. Lett, 43(2), 213--218.
• Kent, A. J., Egan, A., McInerney, J. G., & Moloney, J. V. (1998). Enhanced diffraction limited output power of tapered gain semiconductor lasers. Optics Express, 2(12), 509-514.
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  PMID: 19381222;Abstract: The spatiotemporal dynamics of linearly and trumpet flared high brightness semiconductor lasers are compared and contrasted using a comprehensive model built up from the microscopic physics. While both devices display complex multi longitudinal mode dynamics, the trumpet flared device is less susceptible to transverse filamentation instabilities and, hence, displays superior time-averaged far-field imaging properties. ©1998 Optical Society of America.
• Kent, A., Egan, A., McInerney, J., & Moloney, J. (1998). Enhanced diffiraction limited output powerof tapered gain semiconductor lasers. Optics express, 2(12), 509--514.
• Mlejnek, M., Wright, E., & Moloney, J. (1998). Dynamic spatial replenishment of femtosecond pulses propagating in air. Optics letters, 23(5), 382--384.
• Mlejnek, M., Wright, E., & Moloney, J. (1998). Femtosecond pulse propagation in argon: A pressure dependence study. Physical Review E, 58(4), 4903.
• Mlejnek, M., Wright, E., & Moloney, J. (1998). Long Distance Propagation in Air Due to Dynamic Spatial Replenishment. Optics and Photonics News, 9(12), 38--39.
• Moloney, J., Egan, A., Ning, C., & Indik, R. (1998). Semiconductor Lasers and Amplifiers-Spontaneous Spatiotemporal Instabilities in Current Modulated Master Oscillator Power Amplifier Lasers. IEEE Photonics Technology Letters, 10(9), 1229--1231.
• Moloney, J., Egan, A., Ning, C., & Indik, R. (1998). Spontaneous spatiotemporal instabilities in current modulated master oscillator power amplifier lasers. Photonics Technology Letters, IEEE, 10(9), 1229--1231.
• Ning, C. Z., Bischoff, S., Koch, S. W., Harkness, G. K., Moloney, J. V., & Chow, W. W. (1998). Microscopic modeling of vertical-cavity surface-emitting lasers: Many-body interaction, plasma heating, and transverse dynamics. Optical Engineering, 37(4), 1175-1181.
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  Abstract: A microscopic theory for the interaction between semiconductor quantum-well structures and laser fields based on the semiconductor Bloch equations is applied to vertical-cavity surface-emitting lasers (VCSELs) with the inclusion of plasma heating. The semiconductor Bloch equations are reduced to a set of equations for the first and second moments of the carrier distribution functions. Plasma heating and many-body effects are then studied by solving this set of equations in steady state under the approximation of a single transverse and longitudinal mode. The transverse- and longitudinal-mode dynamics of VCSELs is analyzed by solving the full space-time-dependent problem. © 1998 Society of Photo-Optical Instrumentation Engineers.
• Ning, C., Bischoff, S., Harkness, G., Chow, W. W., Moloney, J. V., & Koch, S. W. (1998). Microscopic modeling of vertical-cavity surface-emitting lasers: many-body interaction, plasma heating, and transverse dynamics. Optical Engineering, 37(4), 1175--1181.
• R\"ossler, T., Indik, R., Harkness, G., Moloney, J., & Ning, C. (1998). Modeling the interplay of thermal effects and transverse mode behavior in native-oxide-confined vertical-cavity surface-emitting lasers. Physical Review A, 58(4), 3279.
• Roessler, T., White, J., Indik, R., & Moloney, J. (1998). Multimode nonlinear dynamics in semiconductor lasers: From patterns to chaos. ASIAN JOURNAL OF PHYSICS, 7, 539--561.
• Rossler, T., Indik, R., Harkness, G., Moloney, J., & Ning, C. (1998). ARTICLES-Quantum optics, physics of lasers, nonlinear optics-Modeling the interplay of thermal effects and transverse mode behavior in native-oxide-confined vertical-cavity surface-emitting lasers. Physical Review-Section A-Atomic Molecular and Optical Physics, 58(4), 3279--3292.
• White, J. K., Moloney, J. V., Gavrielides, A., Kovanis, V., Hohl, A., & Kalmus, R. (1998). Multilongitudinal-mode dynamics in a semiconductor laser subject to optical injection. IEEE Journal of Quantum Electronics, 34(8), 1469-1473.
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  Abstract: Multilongitudinal-mode dynamics in a semiconductor laser subject to optical injection are investigated both experimentally and numerically. We found that there are parameter regimes for which the slave laser hops into an adjacent longitudinal mode as we vary the detuning of the optical frequencies between the master and slave laser. A traveling wave model is used to numerically investigate the mode hopping. Good qualitative agreement is found between the numerical computations and the experimental observations.
• White, J. K., Moloney, J., Gavrielides, A., Kovanis, V., Hohl, A., & Kalmus, R. (1998). Multilongitudinal-mode dynamics in a semiconductor laser subject to optical injection. Quantum Electronics, IEEE Journal of, 34(8), 1469--1473.
• Xin, J., & Moloney, J. (1998). Global solutions and attractors of a Maxwell-Bloch Raman laser system in two transverse dimensions. Nonlinearity, 11(3), 501-527.
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  Abstract: We study a Maxwell-Bloch system describing the dynamics of single-longitudinal Raman lasers in the two transverse space dimensions. Raman lasing is generated by a coherent external pump laser, as a three-wave interaction involving two optical and one material wave. On the other hand, a two-level laser involves incoherent external pumping through, for example, an electrical discharge or flashlamp. Raman lasers have the advantage of being tunable and display a novel explicit nonlinear detuning between the pump and laser emission frequencies. Consequently these lasers exhibit much richer nonlinear dynamics. We establish the global existence of classical H2 solutions, and show that for periodic domains the dynamics is governed by a global C∞ smooth attractor of finite dimensions. We explain the structures of nonlinear interactions and couplings that lead to the time asymptotic smoothing. We also construct mild solutions with the dispersive Strichartz inequality for rough but spatially decaying data (in H1' x (L2∩Lp)2, p ∈ (4, ∞)) on the whole plane, which physically corresponds to the absorbing boundary condition.
• Xin, J., & Moloney, J. (1998). Global solutions and attractors of a Maxwell-Bloch Raman laser system in two transverse dimensions. Nonlinearity, 11(3), 501.
• Aranson, I., Hochheiser, D., & Moloney, J. (1997). Boundary-driven selection of patterns in large-aspect-ratio lasers. Physical Review A, 55(4), 3173.
• Aranson, I., Hochheiser, D., & Moloney, J. V. (1997). Boundary-driven selection of patterns in large-aspect-ratio lasers. Physical Review A - Atomic, Molecular, and Optical Physics, 55(4), 3173-3176.
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  Abstract: Pattern selection in wide aperture lasers is provided by active sources of traveling waves. Finite absorbing transverse boundaries select near-field lasing patterns from a one-parameter continuous family of allowed modes. The selected pattern on the boundary invades the interior consuming any spiral waves that are formed in this region. As a result, only simple stationary patterns are established in nonstiff lasers.
• Bleich, M. E., Hochheiser, D., Moloney, J. V., & Socolar, J. E. (1997). Controlling extended systems with spatially filtered, time-delayed feedback. Physical Review E - Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics, 55(3 SUPPL. A), 2119-2126.
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  Abstract: We investigate a control technique for spatially extended systems combining spatial filtering with a previously studied form of time-delay feedback. The scheme is naturally suited to real-time control of optical systems. We apply the control scheme to a model of a transversely extended semiconductor laser in which a desirable, coherent traveling-wave state exists, but is a member of a nowhere stable family. Our scheme stabilizes this state and directs the system towards it from realistic, distant, and noisy initial conditions. As confirmed by numerical simulation, a linear stability analysis about the controlled state accurately predicts when the scheme is successful and illustrates some key features of the control including the individual merit of, and interplay between, the spatial and temporal degrees of freedom in the control.
• Bleich, M., Hochheiser, D., Moloney, J., & Socolar, J. (1997). Controlling extended systems with spatially filtered, time-delayed feedback. Physical Review E, 55(3), 2119.
• Feng, Q., Moloney, J., Newell, A., Wright, E., Cook, K., Kennedy, P., Hammer, D., Rockwell, B., & Thompson, C. (1997). Theory and simulation on the threshold of water breakdown induced by focused ultrashort laser pulses. Quantum Electronics, IEEE Journal of, 33(2), 127--137.
• Hochheiser, D., Moloney, J., & Lega, J. (1997). Controlling optical turbulence. Physical Review A, 55(6), R4011.
• Komarova, N. L., Malomed, B. A., Moloney, J., & Newell, A. C. (1997). Resonant quasiperiodic patterns in a three-dimensional lasing medium. Physical Review A, 56(1), 803.
• Moloney, J., Indik, R., & Ning, C. (1997). Full space-time simulation for high-brightness semiconductor lasers. Photonics Technology Letters, IEEE, 9(6), 731--733.
• Ning, C., Chow, W., Bossert, D. J., Indik, R., & Moloney, J. (1997). Influences of unconfined states on the optical properties of quantum-well structures. Selected Topics in Quantum Electronics, IEEE Journal of, 3(2), 129--135.
• Ning, C., Indik, R., & Moloney, J. (1997). Effective Bloch equations for semiconductor lasers and amplifiers. Quantum Electronics, IEEE Journal of, 33(9), 1543--1550.
• Ning, C., Moloney, J., Egan, A., & Indik, R. (1997). A first-principles fully space-time resolved model of a semiconductor laser. Quantum and Semiclassical Optics: Journal of the European Optical Society Part B, 9(5), 681.
• Skovgaard, P., McInerney, J., Moloney, J., Indik, R., & Ning, C. (1997). Enhanced stability of MFA-MOPA semiconductor lasers using a nonlinear, trumpet-shaped flare. Photonics Technology Letters, IEEE, 9(9), 1220--1222.
• Bleich, M. E., Hochheiser, D., Moloney, J. V., & Socolar, J. E. (1996). Controlling extended systems with spatially filtered, time-delayed feedback. arXiv preprint chao-dyn/9612013.
• Flesch, R. G., Pushkarev, A., & Moloney, J. V. (1996). Carrier wave shocking of femtosecond optical pulses. Physical Review Letters, 76(14), 2488-2491.
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  Abstract: Numerical integration of Maxwell's equations for propagation of a femtosecond pulse in a medium with linear Lorentz response and a Kerr nonlinearity shows shock formation on the underlying carrier wave prior to the envelope shock. The carrier shock is characterized by the appearance of a strong third harmonic pulse, whereas the envelope shock appears later as spectral broadening and modulation of the fundamental and higher harmonic spectral features.
• Homar, M., Moloney, J. V., & Miguel, M. S. (1996). Traveling wave model of a multimode Fabry-Pérot laser in free running and external cavity configurations. IEEE Journal of Quantum Electronics, 32(3), 553-566.
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  Abstract: We report the results of a numerical study of multimode behavior of a Fabry-Pérot laser. The model is based on traveling-wave equations for the slowly varying amplitudes of the counterpropagating waves in the cavity, coupled to equations for spatially dependent population inversion and polarization of a two-level active medium. Variations in the material variables on the scale of a wavelength are taken into account by means of an expansion in a Fourier series. Results are given for typical semiconductor laser parameters. Spatially distributed spontaneous emission noise and carrier diffusion are taken into account. The competing roles of Spatial Hole Burning (SHB), spontaneous emission noise, and carrier diffusion in determining multimode behavior are elucidated; with no carrier diffusion, spontaneous emission noise excites a large number of modes close to threshold, while SHB leads to a fixed number of significant lasing modes well above threshold. Carrier diffusion washes out the gratings in the material variables, and the resulting strengthening of the inter-mode coupling (cross-saturation) restores dominant single-mode emission well above threshold. We have also studied the effects of optical feedback and opportunities for mode selection with short external cavities; for an external cavity much shorter than the laser cavity length and a small field amplitude reflectivity coefficient, a single mode can be selected. For a large reflectivity coefficient, two groups of intracavity modes separated by the external cavity mode interspacing are selected. For an external cavity with a round trip time half that of the laser cavity, the laser can be forced with modest feedback to operate on two modes that are both quasiresonant with the external cavity. Mode selection is not found, even for weak feedback, when the external mode spacing is about 90% of the laser mode spacing.
• Homar, M., Moloney, J., & San Miguel, M. (1996). Travelling wave model of a multimode Fabry-Perot laser in free running and external cavity configurations. Quantum Electronics, IEEE Journal of, 32(3), 553--566.
• Hughes, S., Knorr, A., Koch, S., Binder, R., Indik, R., & Moloney, J. (1996). The influence of electron-hole-scattering on the gain spectra of highly excited semiconductors. Solid state communications, 100(8), 555--559.
• Indik, R., Binder, R., Mlejnek, M., Moloney, J., Hughes, S., Knorr, A., & Koch, S. (1996). Role of plasma cooling, heating, and memory effects in subpicosecond pulse propagation in semiconductor amplifiers. Physical Review A, 53(5), 3614.
• Xin, J., & Moloney, J. (1996). Global weak solutions and attractors of the three dimensional Maxwell-Bloch two level laser systems. Communications in Mathematical Physics, 179(2), 511-528.
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  Abstract: The three-dimensional Maxwell-Bloch system governs the multi-longitudinal and transverse mode dynamics of two level wide aperture lasers in an optical ring cavity. The system is hyperbolic in the propagation direction, and dispersive in the transverse directions due to diffraction effects. A rich variety of optical patterns and chaos are present in the dynamics. We show the global existence of weak solutions in Lp (2 ≦ p < ∞) spaces of the Maxwell-Bloch system under both absorbing and periodic boundary conditions. The weak solutions are unique within the class of solutions provided by our regularization procedure and approach a universal attractor which has only partial smoothing instead of the C∞ smoothing property found in early works for the (longitudinal) one-dimensional and (transverse) two-dimensional cases. The idea of the proof makes essential use of both the hyperbolicity and dispersivity of the system. In the case of periodic boundary condition, our result depends on a conjectural Strichartz inequality.
• Xin, J., & Moloney, J. (1996). Global weak solutions and attractors of the three dimensional Maxwell-Bloch two level laser systems. Communications in mathematical physics, 179(2), 511--528.
• Chow, W., Indik, R., Knorr, A., Koch, S., & Moloney, J. (1995). Time-resolved nondegenerate four-wave mixing in a semiconductor amplifier. Physical Review A, 52(3), 2479.
• Feng, Q., Wright, E., Moloney, J., & Newell, A. (1995). Laser-induced breakdown versus self-focusing for focused picosecond pulses in water. Optics letters, 20(19), 1958--1960.
• Hess, O., Koch, S. W., & Moloney, J. V. (1995). Filamentation and beam propagation in broad-area semiconductor lasers. IEEE Journal of Quantum Electronics, 31(1), 35-43.
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  Abstract: The spatio-temporal dynamics of broad-area semiconductor lasers is studied theoretically by numerically solving space-dependent coupled partial differential equations for the (complex) optical fields, the interband polarization and the density of charge carriers. The formation and longitudinal propagation of unstable transverse optical filamentary structures is analyzed in a model configuration for typical double-heterostructure broad-area lasers. Spectral and spatial holeburning in the carrier distributions is observed as a consequence of selective density depletion by the transverse laser modes. The transverse holeburning leads to complex spatio-temporal patterns.
• Hess, O., Koch, S., & Moloney, J. (1995). Filamentation and beam propagation in broad-area semiconductor lasers. Quantum Electronics, IEEE Journal of, 31(1), 35--43.
• Indik, R., Binder, R., Knorr, A., Koch, S., & Moloney, J. (1995). Self-induced channeling of subpicosecond optical pulses in broad-area bulk semiconductor amplifiers. Optics letters, 20(22), 2315--2317.
• Lega, J., Moloney, J., & Newell, A. (1995). Universal description of laser dynamics near threshold. Physica D: Nonlinear Phenomena, 83(4), 478--498.
• Miguel, M. S., Feng, Q., & Moloney, J. V. (1995). Light-polarization dynamics in surface-emitting semiconductor lasers. Physical Review A - Atomic, Molecular, and Optical Physics, 52(2), 1728-1739.
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  Abstract: A four-level model for the dynamics of single longitudinal mode, surface-emitting, quantum well semiconductor lasers is introduced. The model generally predicts linearly polarized laser emission for a perfectly isotropic cavity. The stability and dynamical response to fluctuations of the linearly polarized states is determined by the ratio of time scales associated with spontaneous decay and with spin relaxation processes.
• Ning, C. Z., & Moloney, J. V. (1995). Plasma-heating induced intensity-dependent gain in semiconductor lasers. Applied Physics Letters, 559-.
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  Abstract: Starting from a set of equations derived from a microscopic theory we show that the familiar nonlinear gain of the form a/(1+I/Is) introduced in semiconductor laser rate equations phenomenologically should be replaced by a more general form of a/(1+I/Is)b. The new scaling exponent b depends on the relaxation constant γT that describes the rate of heat dissipation from plasma to the lattice due to carrier-phonon scattering. © 1995 American Institute of Physics.
• Ning, C., & Moloney, J. (1995). Plasma-heating induced intensity-dependent gain in semiconductor lasers. Applied physics letters, 66(5), 559--561.
• Ning, C., & Moloney, J. (1995). Thermal effects on the threshold of vertical-cavity surface-emitting lasers: first-and second-order phase transitions. Optics letters, 20(10), 1151--1153.
• Ning, C., Indik, R., & Moloney, J. (1995). Self-consistent approach to thermal effects in vertical-cavity surface-emitting lasers. JOSA B, 12(10), 1993--2004.
• San Miguel, M., Feng, Q., & Moloney, J. (1995). Light-polarization dynamics in surface-emitting semiconductor lasers. Physical Review A, 52(2), 1728.
• White, J. K., McInerney, J. G., & Moloney, J. V. (1995). Effects of the injection current profile shape on sidelobes in large-aperture semiconductor laser amplifiers. Optics Letters, 20(6), 593-595.
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  Abstract: Sharply peaked sidelobes limit power in the central lobe for both flared and unflared single-pass semiconductor laser amplifiers. A model recently developed by the authors have shown that sidelobes appear when the injected field pattern overfills the input aperture, suggesting that the phenomenon is a result of interaction of the field with the sharp edge of the carrier density profile in the lateral direction. In this paper, the effects of a transverse pattern propagating through an unsaturated amplifier are explored. It is shown that sidelobes are formed whose magnitude depends on the first and second derivatives of the transverse carrier density distribution. These sidelobes then seed the nonlinear growth of the sidelobes in the saturated case. Results of numerical simulations are given in which the amplifier current distribution have been smoothed about the edges. As predicted, the sidelobes are reduced.
• White, J. K., McInerney, J. G., & Moloney, J. V. (1995). Formation of sharply peaked sidelobes in large aperture single-pass semiconductor laser amplifiers. Electronics Letters, 31(1), 38-39.
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  Abstract: Single-pass semiconductor laser amplifiers are shown theoretically to exhibit sharply peaked lobes ('bat ears') at the edges of the near-field output. We discuss the mechanism for their formation and show that it is qualitatively different from spontaneous filamentation in homogeneous media.
• White, J., McInerney, J., & Moloney, J. (1995). Effects of the injection current profile shape on sidelobes in large-aperture semiconductor laser amplifiers. Optics letters, 20(6), 593--595.
• White, J., McInerney, J., & Moloney, J. (1995). Formation of sharply peaked sidelobes in large aperture single-pass semiconductor laser amplifiers. Electronics Letters, 31(1), 38--39.
• Feng, Q., Moloney, J., & Newell, A. (1994). Transverse patterns in lasers. Physical Review A, 50(5), R3601.
• Geddes, J. B., Indik, R., Moloney, J., & Firth, W. J. (1994). Hexagons and squares in a passive nonlinear optical system. Physical Review A, 50(4), 3471.
• Geddes, J., Lega, J., Moloney, J., Indik, R., Wright, E., & Firth, W. (1994). Pattern selection in passive and active nonlinear optical systems. Chaos, Solitons \& Fractals, 4(8), 1261--1274.
• Geddes, J., Moloney, J., Wright, E., & Firth, W. (1994). Polarisation patterns in a nonlinear cavity. Optics communications, 111(5), 623--631.
• Geddes, J., Moloney, J., Wright, E., & Firth, W. (1994). Polarization patterns in a nonlinear cavity. OPTICS COMMUNICATIONS, 111(5-6), 623--631.
• Harkness, G., Firth, W. J., Geddes, J. B., Moloney, J., & Wright, E. (1994). Boundary effects in large-aspect-ratio lasers. Physical Review A, 50(5), 4310.
• Indik, R., Knorr, A., Binder, R., Moloney, J., & Koch, S. (1994). Propagation-induced adiabatic following in a semiconductor amplifier. Optics letters, 19(13), 966--968.
• Jakobsen, P., Lega, J., Feng, Q., Staley, M., Moloney, J., & Newell, A. (1994). Nonlinear transverse modes of large-aspect-ratio homogeneously broadened lasers: I. Analysis and numerical simulation. Physical Review A, 49(5), 4189.
• Lega, J., Jakobsen, P., Moloney, J., & Newell, A. (1994). Nonlinear transverse modes of large-aspect-ratio homogeneously broadened lasers: II. Pattern analysis near and beyond threshold. Physical Review A, 49(5), 4201.
• Lega, J., Moloney, J., & Newell, A. (1994). Swift-Hohenberg equation for lasers. Physical review letters, 73(22), 2978.
• Luther, G., Newell, A., & Moloney, J. (1994). The effects of normal dispersion on collapse events. Physica D: Nonlinear Phenomena, 74(1), 59--73.
• Luther, G., Wright, E., Moloney, J., & Newell, A. (1994). Self-focusing threshold in normally dispersive media. Optics letters, 19(12), 862--864.
• Luther, G., Wright, E., Newell, A., & Moloney, J. (1994). Short-pulse conical emission and spectral broadening in normally dispersive media. Optics letters, 19(11), 789--791.
• Powell, J. A., Wright, E., & Moloney, J. (1994). Reflection of localized beams from a nonlinear absorbing interface. SIAM Journal on Applied Mathematics, 54(3), 774--788.
• Ru, P., Chow, W. W., Moloney, J. V., & Koch, S. W. (1994). Quantum confinement and strain effects on the lateral mode stability of an unstable resonator semiconductor laser. Applied Physics Letters, 64(12), 1469-1471.
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  Abstract: This paper addresses the question of how the gain structure affects the lateral mode stability of an unstable resonator semiconductor laser, particularly the effects of quantum confinement and strain. This is aimed at determining the gain structure more tolerant to the optical resonator geometry or one which allow single mode operation at a higher excitation. A laser model based on a many-body theory of the optical properties of semiconductors was used. Applying this theory to a variety of semiconductor materials, the absorption, gain, and refractive index spectra were computed and compared to experimental data.
• Ru, P., Chow, W., Moloney, J., & Koch, S. (1994). Quantum confinement and strain effects on the lateral mode stability of an unstable resonator semiconductor laser. Applied physics letters, 64(12), 1469--1471.
• Ru, P., Moloney, J., & Indik, R. (1994). Mean-field approximation in semiconductor laser modeling. Physical Review A, 50(1), 831.
• Wang, C., Trivedi, S., Bertolotti, M., Masciulli, P., Sibilia, C., Hell, S. W., Wichmann, J., Soan, P., Damzen, M., Aboites, V., & others, . (1994). GENERAL OPTICS Expression of the kernel of a fractional Fourier transform in elementary functions Control of wave-front propagation with diflractive elements Optical phase-lock loops with photoconductive semiconductor. Optics Letters, 19, 848.
• Adachihara, H., Hess, O., Abraham, E., Ru, P., & Moloney, J. (1993). Spatiotemporal chaos in broad-area semiconductor laser. JOSA B, 10(4), 658--665.
• Adachihara, H., Hess, O., Abraham, E., Ru, P., & Moloney, J. V. (1993). Spatiotemporal chaos in broad-area semiconductor lasers. Journal of the Optical Society of America B: Optical Physics, 10(4), 658-665.
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  Abstract: This paper analyses numerically the nonlinear dynamics of broad-area semiconductor lasers with a solution of the phenomenological laser model developed by combining the electron-hole pair concentration dynamics (including diffusion) with Maxwell's equations for transversely diffracting cavity counterpropagating optical fields. Results show that spatiotemporal chaos is exhibited by the output intensity profile, which can be suppressed by the introduction of a small confinement factor and/or enhancing the linewidth. Experimental results are in agreement with simulation findings that prove that an appropriate mirror curvature brings stability to a half-symmetric unstable resonator.
• Adachihara, H., Hess, O., Indik, R., & Moloney, J. (1993). Semiconductor laser array dynamics: numerical simulations on multistripe index-guided lasers. JOSA B, 10(3), 496--506.
• Ehrlich, J., Valera, J., Adachihara, H., Moloney, J., & Walker, A. (1993). Nonlinear Refraction and Absorption in 4BCMU Planar Waveguides at 1\textperiodcentered 064 $\mu$m Wavelength. Journal of Modern Optics, 40(11), 2151--2160.
• Feng, Q., Moloney, J., & Newell, A. (1993). Amplitude instabilities of transverse traveling waves in lasers. Physical review letters, 71(11), 1705.
• Moloney, J., Jakobsen, P., Lega, J., Wenden, S., & Newell, A. (1993). Space-time complexity in nonlinear optics. Physica D: Nonlinear Phenomena, 68(1), 127--134.
• Powell, J. A., Moloney, J. V., Newell, A. C., & Albanese, R. A. (1993). Beam collapse as an explanation for anomalous ocular damage. JOSA B, 10(7), 1230--1241.
• Ru, P., Jakobsen, P., Moloney, J. V., & Indik, R. (1993). Generalized coupled-mode model for the multistripe index-guided laser arrays. JOSA B, 10(3), 507--515.
• Ru, P., Moloney, J., Indik, R., Koch, S., & Chow, W. (1993). Microscopic modelling of bulk and quantum-well GaAs-based semiconductor lasers. Optical and quantum electronics, 25(10), 675--693.
• Rzhanov, Y. A., & Moloney, J. (1993). Coherent photon seeding in a colour-centre laser. Optical and quantum electronics, 25(1), 63--74.
• Rzhanov, Y. A., Richardson, H., Hagberg, A., & Moloney, J. (1993). Spatiotemporal oscillations in a semiconductor \'etalon. Physical Review A, 47(2), 1480.
• Rzhanov, Y., & Moloney, J. V. (1993). Coherent photon seeding in a colour-centre laser. Optical and Quantum Electronics, 25(1), 63-74.
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  Abstract: We report on a full-scale numerical simulation of the coherent photon seeding technique applied to colour-centre lasers with counterpropagating beams. The stabilization technique is proved to be simple and efficient independently of the interferometric precision of the coupled cavity. © 1993 Chapman & Hall.
• Rzhanov, Y., Richardson, H., Hagberg, A. A., & Moloney, J. V. (1993). Spatiotemporal oscillations in a semiconductor étalon. Physical Review A, 47(2), 1480-1491.
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  Abstract: We show theoretically that competing optical nonlinearities in a semiconductor étalon, with transverse effects included, result in complex spatiotemporal behavior. A theoretical framework is developed that explains many features of the oscillatory behavior. Numerical simulations exhibit kinks, switching waves, whole-beam, and edge oscillations. Simulations compare favorably with recent experiments. © 1993 The American Physical Society.
• Varatharajah, P., Moloney, J. V., Newell, A., & Wright, E. M. (1993). Stationary nonlinear waves guided by thin films bounded by nonlinear diffusive media. JOSA B, 10(1), 46--54.
• Aceves, A. B., & Moloney, J. V. (1992). Effect of two-photon absorption on bright spatial soliton switches. Optics letters, 17(21), 1488--1490.
• Chang, R., Firth, W., Indik, R., Moloney, J., & Wright, E. (1992). Three-dimensional simulations of degenerate counterpropagating beam instabilities in a nonlinear medium. Optics communications, 88(2), 167--172.
• Forysiak, W., & Moloney, J. V. (1992). Dynamics of synchronously pumped mode-locked color-center lasers. Physical Review A, 45(5), 3275-3288.
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  Abstract: Numerical simulations of mode locking in synchronously pumped Tl0(1) color-center lasers are presented. An asymmetric response with respect to cavity mismatch and the origin of large-scale fluctuations in spontaneous-emission noise are described. It is shown that quasistationary pulse trains may be obtained on cavity tuning without a degradation in pulse quality. © 1992 The American Physical Society.
• Forysiak, W., & Moloney, J. V. (1992). Mode-locking dynamics of synchronously pumped color-center lasers: Fabry-Pérot and ring geometries. Physical Review A, 45(11), 8110-8120.
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  Abstract: Numerical simulations of mode locking in synchronously pumped KCl:Tl0(1) and LiF:F2+ color-center lasers in Fabry-Pérot and ring configurations are presented. The presence of spontaneous-emission noise leads to large-scale fluctuations in the resulting pulses, and conditions for pulse optimization and stabilization are described. There exists a close correspondence between regimes of quasistationary and fluctuating pulses in the Fabry-Pérot and unidirectional ring lasers, with regimes of quasistationary, spontaneously unidirectional and stochastically driven, competitive, bidirectional pulsing in the bidirectional lasers. © 1992 The American Physical Society.
• Geddes, J., Moloney, J., & Indik, R. (1992). Spontaneous transverse spatial pattern formation due to stimulated Brillouin scattering of counterpropagating optical beams. Optics communications, 90(1), 117--122.
• Jakobsen, P., Moloney, J., Newell, A., & Indik, R. (1992). Space-time dynamics of wide-gain-section lasers. Physical Review A, 45(11), 8129.
• Moloney, J., Newell, A., & Aceves, A. (1992). Spatial soliton optical switches: a soliton-based equivalent particle approach. Optical and quantum electronics, 24(11), S1269--S1293.
• Newell, A. C., & Moloney, J. V. (1992). Nonlinear optics.
• Forysiak, W., Moloney, J. V., & Harrison, R. G. (1991). Bifurcations of an optically pumped three-level laser model. Physica D: Nonlinear Phenomena, 53(1), 162-186.
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  Abstract: We study the bifurcations in a sixth-order model of a resonant, homogeneously broadened, three-level, optically pumped laser. Standard analytical and numerical techniques are used to obtain a complete unfolding of the model's equilibrium bifurcations in its four-dimensional parameter space. Regions of stationary, periodic and potentially chaotic behaviour are then readily identified. Turning to two specific cases, we study the principal global bifurcations in a two-parameter plane and show their origin in special degenerate bifurcation points of codimension two. The different relative dispositions of the principal homoclinic and heteroclinic connections in these two examples result in different local bifurcation behaviours and chaotic dynamics, which we illustrate in detail. © 1991.
• Jakobsen, P., Indik, R., Moloney, J. V., Newell, A. C., Winful, H. G., & Raman, L. (1991). Diode-laser array modes: discrete and continuous models and their stability. JOSA B, 8(8), 1674--1680.
• Aceves, A., Varatharajah, P., Newell, A., Wright, E., Stegeman, G., Heatley, D., Moloney, J., & Adachihara, H. (1990). Particle aspects of collimated light channel propagation at nonlinear interfaces and in waveguides. JOSA B, 7(6), 963--974.
• Adachihara, H., Moloney, J. V., & Polky, J. N. (1990). Pulsed spatial switching at the interface separating Kerr-like instantaneous and relaxing dielectric media. Physical Review A, 41(9), 5000-5011.
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  Abstract: Propagation of optical pulses, both Gaussian and square in time, at an oblique angle to the interface separating two nonlinear self-focusing media, is studied numerically. The role of a finite-medium response in determining the reflection and transmission asymptotics of the pulse is established, and it is confirmed that, in the limit of a negligible Debye relaxation time, the equivalent particle theory for cw incident beams applies. Examples of spatially distributed multiplexing and demultiplexing of optical pulse trains illustrate the usefulness of the equivalent-particle picture in designing novel optical switching architectures. © 1990 The American Physical Society.
• Adachihara, H., Moloney, J., & Polky, J. (1990). Pulsed spatial switching at the interface separating Kerr-like instantaneous and relaxing dielectric media. Physical Review A, 41(9), 5000.
• Balkarei, Y. I., Evtikhov, M., Moloney, J., & Rzhanov, Y. A. (1990). Self-focusing effects in a bistable semiconductor interferometer. JOSA B, 7(7), 1298--1302.
• Harrison, R. G., Uppal, J. S., Johnstone, A., & Moloney, J. V. (1990). Evidence of chaotic stimulated brillouin scattering in optical fibers. Physical Review Letters, 65(2), 167-170.
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  Abstract: We report first evidence in support of chaotic stimulated Brillouin scattering under cw pump conditions involving a single Stokes and pump signal. A single-mode optical fiber is used as the nonlinear medium. The inclusion of external optical feedback modifies the form of the chaotic dynamics and results in a rich variety of classifiable precursor dynamical features.
• Mitchell, C. S., & Moloney, J. V. (1990). Propagation and stability of optical pulses in nonlinear planar structures with instantaneous and finite response times. IEEE Journal of Quantum Electronics, 26(12), 2115-2129.
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  Abstract: The propagation of optical pulses in nonlinear waveguide and directional coupler structures consisting of linear and self-focusing media is studied numerically. Instantaneous and integrating nonlinearities are considered. A comparison of the stability of waveguide modes and coupling characteristics under such conditions is made. Finite medium response times are shown to lead to an increase in the stability of pulses propagating in waveguide structures. For directional coupler geometries it is shown that finite response times lead to a loss of definition between the cross and bar states as the coupling efficiencies of more intense pulses are increased. These effects are found to be dependent on the initial, spatial, and temporal pulse profiles.
• Mitchell, C., & Moloney, J. (1990). Propagation and stability of optical pulses in nonlinear planar structures with instantaneous and finite response times. Quantum Electronics, IEEE Journal of, 26(12), 2115--2129.
• Moloney, J. V., & Newell, A. C. (1990). Nonlinear optics. Physica D: Nonlinear Phenomena, 44(1), 1--37.
• Moloney, J., Adachihara, H., Indik, R., Lizarraga, C., Northcutt, R., McLaughlin, D., & Newell, A. (1990). Modulational-induced optical pattern formation in a passive optical-feedback system. JOSA B, 7(6), 1039--1044.
• Varatharajah, P., Aceves, A. B., Moloney, J. V., & Wright, E. M. (1990). Stationary nonlinear surface waves and their stability in diffusive Kerr-like nonlinear media. JOSA B, 7(2), 220--229.
• Varatharajah, P., Newell, A., Moloney, J., & Aceves, A. (1990). Transmission, reflection, and trapping of collimated light beams in diffusive Kerr-like nonlinear media. Physical Review A, 42(3), 1767.
• Aceves, A., Moloney, J., & Newell, A. (1989). THEORY OF LIGHT-BEAM PROPAGATION AT NONLINEAR INTERFACES. 2. MULTIPLE-PARTICLE AND MULTIPLE-INTERFACE EXTENSIONS. Physical Review A, 39(4), 1828--1840.
• Aceves, A., Moloney, J., & Newell, A. (1989). Theory of light-beam propagation at nonlinear interfaces. I. Equivalent-particle theory for a single interface. Physical Review A, 39(4), 1809.
• Forysiak, W., Harrison, R. G., & Moloney, J. V. (1989). Local bifurcations of a three-level optically pumped laser. Physical Review A, 39(1), 421-423.
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  Abstract: We report on a linear-stability analysis of a three-level, resonantly optically pumped, homogeneously broadened, single-mode laser. We identify the relatively simple nature of the local bifurcations on the nonlasing branch comprising pitchfork, Hopf, and codimension-2 bifurcations. Their use is demonstrated in identifying regions of parameter space in which we may expect steady, periodic, and more complex dynamical behavior. © 1989 The American Physical Society.
• MOLONEY, J. V., & NEWELL, A. C. (1989). NQNLINEAR OPTICS.
• Mitchell, C. S., & Moloney, J. V. (1989). Propagation characteristics of optical beams in planar thin-film waveguides. Optics Communications, 69(3-4), 243-246.
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  Abstract: We study numerically the propagation of an optical beam propagating at an oblique angle of incidence to the guide axis in nonlinear thin-film dielectric waveguides. Our results show that the behaviour of the incident beam can be characterised in terms of an equivalent particle moving in an equivalent potential. © 1989.
• Mitchell, C., & Moloney, J. (1989). Propagation characteristics of optical beams in planar thin-film waveguides. Optics communications, 69(3), 243--246.
• Moloney, J. V., Forysiak, W., Uppal, J. S., & Harrison, R. G. (1989). Regular and chaotic dynamics of optically pumped molecular lasers. Physical Review A, 39(3), 1277-1285.
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  Abstract: We present a detailed analysis of the dynamical behavior of an optically pumped molecular laser. This study combines bifurcation and power spectral analysis with numerical investigation of the global features of attractor topology under control parameter variation. The special role of the pump laser in generating physically distinct periodic and chaotic dynamics is emphasized through the complementary use of laser gain and dispersion characteristics. Our main results are the following: (i) instabilities associated with the physically distinct mechanisms of relaxation and pump-induced Rabi sideband oscillations are readily generated; (ii) the topological characteristics of both periodic and chaotic attractors reflect these physically distinct mechanisms, making it possible to discriminate between both types of behavior in heterodyne power spectra; and (iii) the ratio of deenergization to dipole-dephasing rates is central to determining the operating characteristics of the laser. © 1989 The American Physical Society.
• Varatharajah, P., Aceves, A. B., & Moloney, J. V. (1989). All-optical spatial scanner. Applied Physics Letters, 54(26), 2631-2633.
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  Abstract: The design of a simple all-optical spatial scanner, based on a propagating self-focused channel incident at an oblique angle to a nonlinear dielectric interface, is illustrated using the beam propagation method. The channel asymptotics are shown to be insensitive to the shape of the incident beam profile with the latter satisfying a simple area criterion.
• Varatharajah, P., Aceves, A., & Moloney, J. (1989). All-optical spatial scanner. Applied Physics Letters, 54(26), 2631--2633.
• Aceves, A. B., Moloney, J., & Newell, A. (1988). Snell's laws at the interface between nonlinear dielectrics. Physics Letters A, 129(4), 231--235.
• Aceves, A., MOLONEY, J., & NEWELL, A. (1988). Theory of Beam Reflection, Transmission, Trapping and Breakup at Nonlinear Optical Interfaces. Le Journal de Physique Colloques, 49(C2), C2--319.
• Aceves, A., Moloney, J., & Newell, A. (1988). Mathematical modeling of beam reflection, transmission and trapping at nonlinear optical interfaces. Mathematical and Computer Modelling, 11, 101--105.
• Adachihara, H., McLaughlin, D., Moloney, J., & Newell, A. (1988). Solitary waves as fixed points of infinite-dimensional maps for an optical bistable ring cavity: Analysis. Journal of mathematical physics, 29(1), 63--85.
• ETRICH, C., MITCHELL, C., & MOLONEY, J. (1988). OURNAL DE PHYSIQUE tolloque C2, Supplement au n 6, Tome 49, juin 1988 C2-315. Optical Bistability IV: 23-25 March 1988, Aussois (France), 315.
• ETRICH, C., MITCHELL, C., & MOLONEY, J. (1988). PROPAGATION AND STABILITY CHARACTERISTICS OF NONLINEAR GUIDED WAVES IN SATURABLE NONLINEAR MEDIA. Le Journal de Physique Colloques, 49(C2), C2--315.
• MOLONEY, J. (1988). THEORY OF NONLINEAR WAVEGUIDES: STATIONARY AND PROPAGATING WAVES. Le Journal de Physique Colloques, 49(C2), C2--277.
• Ouarzeddini, A., Adachihara, H., & Moloney, J. (1988). Spontaneous spatial symmetry breaking in passive nonlinear optical feedback systems. Physical Review A, 38, 2005--2010.
• Ouarzeddini, A., Adachihara, H., & Moloney, J. V. (1988). Spontaneous spatial symmetry breaking in passive nonlinear optical feedback systems. Physical Review A, 38(4), 2005-2010.
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  Abstract: We show that a previously derived modulational instability formula is universally applicable to nonlinear optical feedback systems. © 1988 The American Physical Society.
• Ouarzeddini, A., Adachihara, H., Moloney, J., Mclaughlin, D., Newell, A., & others, . (1988). Spontaneous spatial symmetry breaking in passive optical feedback systems. Journal de Physique Colloques, 49(C2).
• Uppal, J. S., Harrison, R. G., & Moloney, J. V. (1988). Erratum: Gain, dispersion, and emission characteristics of three-level molecular laser amplifier and oscillator systems (Physical Review A (1988) 37, 11, (4531)). Physical Review A, 37(11), 4531-.
• Varatharajah, P., Heatley, D., Wright, E., Aceves, A., & Moloney, J. (1988). Stationary nonlinear surface waves and their stability in diffusive Kerr media. Optics letters, 13(8), 690--692.
• Moloney, J. V. (1987). Modulational instability of two-transverse-dimensional surface polariton waves in nonlinear dielectric waveguides. Physical Review A, 36(9), 4563-4566.
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  Abstract: It is predicted and confirmed numerically that the nonlinear stationary waves on the surface polariton branch of a thin-film dielectric waveguide are unstable to transverse spatial fluctuations in the dimension parallel to the confining layers. Bounded waves whose peaks are located within the linear thin-film guiding layer show behavior in qualitative agreement with that of earlier studies on the two-dimensional propagation problem. © 1987 The American Physical Society.
• Moloney, J. V., Uppal, J. S., & Harrison, R. G. (1987). Origin of chaotic relaxation oscillations in an optically pumped molecular laser. Physical Review Letters, 59(25), 2868-2871.
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  Abstract: We show that pump-induced modifications to the gain and dispersion profiles can induce a weak side-band modulation which acts as a driving term to sustain chaotic relaxation oscillations in a single-mode, resonant, optically pumped molecular laser. Our study suggests that a careful two- or more-parameter unfolding of higher-codimension bifurcations should lead to a wealth of nonlinear dynamical behavior within easy access of current experiments. © 1987 The American Physical Society.
• Moloney, J., Adachihara, H., McLaughlin, D., & Newell, A. (1987). Fixed points and chaotic dynamics of an infinite dimensional map. Choas, Noise and Fractals, 1, 137.
• Uppal, J. S., Harrison, R. G., & Moloney, J. V. (1987). Gain, dispersion, and emission characteristics of three-level molecular laser amplifier and oscillator systems. Physical Review A, 36(10), 4823-4834.
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  Abstract: Interaction of two coherent fields of arbitrary intensity with a general homogeneously broadened three-level molecular system for both an amplifier as well as a laser oscillator under general conditions of pumping is discussed. The amplifier solution is obtained through the time-averaged density-matrix formalism with two coherent fields treated classically. A detailed consideration of both real and imaginary parts of the electric susceptibility at pump and emission frequencies, corresponding to gain and dispersion in the active medium has been taken into account. The results obtained are used to study a number of situations for weak and strong pumping in the laser amplifier. Subsequently these are applied to a mode analysis of a unidirectional single-mode laser oscillator to determine the output characteristics of the laser and to establish conditions under which emission becomes dynamically unstable resulting in sustained oscillatory emission. The results obtained are found to be in good agreement with those of a full numerical analysis of the atomic and field coupled equations describing the system. © 1987 The American Physical Society.
• Uppal, J. S., Harrison, R. G., & Moloney, J. V. (1987). Validity of mode splitting analysis in optically pumped molecular lasers having Rabi splitting. Optics Communications, 64(4), 357-361.
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  Abstract: Mode splitting analysis of three-level optically pumped molecular lasers is shown to provide both a clear physical insight and a quantitative measure of the steady state and oscillatory emission characteristics predicted from numerical analysis of these systems. © 1987.
• Aceves, A., Adachihara, H., Jones, C., Lerman, J. C., McLaughlin, D. W., Moloney, J. V., & Newell, A. C. (1986). Chaos and coherent structures in partial differential equations. Physica D: Nonlinear Phenomena, 18(1), 85--112.
• Ariyasu, J., Seaton, C. T., Stegeman, G. I., & Moloney, J. V. (1986). NEW THEORETICAL DEVELOPMENTS IN NONLINEAR GUIDED WAVES: STABILITY OF TE//1 BRANCHES.. IEEE Journal of Quantum Electronics, QE-22(6), 984-987.
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  Abstract: The stability is determined for TE//1 , nonlinear, stationary wave solutions in planar optical waveguides with nonlinear substrate and cladding bounding media. The numerical scheme involves propagation of the transverse field distribution corresponding to a standing-wave solution on the appropriate branch of the nonlinear dispersion curve. The results indicate that large regions on the TE//1 branches are unstable. Limited results are also given for a TE//2 branch with a power threshold.
• Ariyasu, J., Stegeman, G. I., Seaton, C. T., & Moloney, J. V. (1986). New theoretical developments in nonlinear guided waves: Stability of TE 1 branches. IEEE Journal of Quantum Electronics, 22(6), 984-987. doi:10.1109/jqe.1986.1073041
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  We determine the stability of TE 1 , nonlinear, stationary wave solutions in planar optical waveguides with nonlinear substrate and cladding bounding media. Our numerical scheme involves propagation of the transverse field distribution corresponding to a standing wave solution on the appropriate branch of the nonlinear dispersion curve. The results indicate that large regions on the TE 1 branches are unstable. Limited results are also given for a TE 2 branch with a power threshold.
• Jones, C. K., & Moloney, J. V. (1986). Instability of standing waves in nonlinear optical waveguides. Physics Letters A, 117(4), 175-180.
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  Abstract: A new mathematical instability technique is presented and applied to determine the stability properties of a physically important class of standing waves in nonlinear planar optical waveguides. The method is illustrated by a case where soliton perturbation techniques or variational methods are inapplicable. © 1986.
• Jones, C., & Moloney, J. (1986). Instability of standing waves in nonlinear optical waveguides. Physics Letters A, 117(4), 175--180.
• Moloney, J. V. (1986). Many-parameter routes to optical turbulence. Physical Review A, 33(6), 4061-4078.
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  Abstract: The output of an externally pumped passive nonlinear-optical ring resonator is known to exhibit chaotic dynamics under variation of one or more external control parameters. The dynamics of the internal transverse laser beam profile is described, in the good-cavity limit, by an infinite-dimensional discrete-time map in function space. We find that the asymptotic dynamical behavior of the internal resonator field is in marked contrast to earlier plane-wave predictions. Instead, self-focusing, self-defocusing nonlinearities, and linear diffraction, combined with the pump and feedback of the ring resonator, give rise to strong spatial modulation of the transverse profile. For a self-focusing nonlinearity, spatially coherent robust transverse solitonlike structures persist even though the beam is undergoing temporally chaotic motion. Using attractor embedding techniques on our numerical solutions, we isolate distinct routes to optical turbulence under variation of a number of different control parameters. In particular, we provide examples of Ruelle-Takens-Newhouse sequences, intermittency, and a nongeneric bifurcation involving period doubling of invariant circles. A main result of the paper is that many few-dimensional attractors can coexist in different regions of the infinite-dimensional phase space at fixed values of the external control parameters. These attractors are accessed by varying the systems initial conditions and can, under variation of an appropriate control parameter, independently undergo transition to chaos. Interaction between neighboring attractors appears to be responsible for numerically observed departures from generic behavior. We note striking similarities between some of our numerically generated instability sequences and recent experimental observations in low-aspect-ratio fluid systems. © 1986 The American Physical Society.
• Moloney, J. V., Ariyasu, J., Seaton, C. T., & Stegeman, G. I. (1986). Numerical evidence for nonstationary, nonlinear, slab-guided waves.. Optics letters, 11(5), 315. doi:10.1364/ol.11.000315
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  Numerical studies of the propagation of waves guided by a thin film bounded by two self-focusing media reveal a whole new class of nonstationary solutions that can, in their own right, propagate as guided-wave fields, some with solitonlike components.
• Moloney, J. V., Ariyasu, J., Seaton, C. T., & Stegeman, G. I. (1986). Stability of nonlinear stationary waves guided by a thin film bounded by nonlinear media. Applied Physics Letters, 48(13), 826-828.
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  Abstract: The stability of stationary, TE0-type, nonlinear, thin-film guided waves was investigated numerically for both symmetric and asymmetric planar waveguides with nonlinear cladding and substrate layers. It is found that large regions of the dispersion curves are unstable at high powers.
• Stegeman, G. I., Seaton, C. T., Ariyasu, J., Shen, T. P., & Moloney, J. V. (1986). Saturation and power law dependence of nonlinear waves guided by a single interface. Optics Communications, 56(5), 365-368.
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  Abstract: The nonlinear waves guided by the interface between a linear and a non-Kerr-like, nonlinear medium were investigated numerically using the formalism recently developed by Langbein et al. [Optics Comm. 53 (1985) 417]. The power dependence of the propagation constant and field distributions were calculated for both power-law and saturable field-dependent dielectric constants. © 1986.
• Moloney, J. (1985). Two-dimensional transverse solitary waves as asymptotic states of the field in a bistable optical resonator. Quantum Electronics, IEEE Journal of, 21(9), 1393--1398.
• Moloney, J. V. (1985). TWO-DIMENSIONAL TRANSVERSE SOLITARY WAVES AS ASYMPTOTIC STATES OF THE FIELD IN A BISTABLE OPTICAL RESONATOR.. IEEE Journal of Quantum Electronics, QE-21(9), 1393-1398.
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  Abstract: The dynamical evolution of a two transverse dimensional laser beam profile is monitored as it switches from a low to a high transmission state in a bistable optical resonator. Sharp gradients appearing at the edge of the switched-on central portion of the beam initiate a train of solitary waves which grow inwards toward the beam center. In a high finesse resonator, strong saturation of the beam in the on state tends to stabilize the solitary waves as concentric rings. Unlike earlier one transverse dimensional studies, the central part of the beam undergoes a slow periodic oscillation, but the shapes of the outer rings are consistent with earlier one transverse dimensional predictions. Numerical evidence is provided for filamentation of lower amplitude rings.
• Moloney, J. V., Jones, C. K., Jones, C. K., & Hammel, S. M. (1985). Global dynamical behavior of the optical field in a ring cavity. Journal of The Optical Society of America B-optical Physics, 2(4), 552-564. doi:10.1364/josab.2.000552
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  A new class of instabilities for a plane-wave intracavity field in an optical ring resonator is identified. Dynamical systems techniques are explained and applied to the map. A bifurcation diagram is given that organizes the important information, and global pictures are developed that describe the evolution of the attractor and its basin boundary. Anomalous behavior observed in earlier numerical studies is explained.
• Stegeman, G. I., Ariyasu, J., Seaton, C. T., Shen, T. P., & Moloney, J. V. (1985). Nonlinear thin-film guided waves in non-Kerr media. Applied Physics Letters, 47(12), 1254-1256.
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  Abstract: The power-dependent wave vector is calculated for nonlinear waves guided by a thin film bounded by media whose dielectric constant varies as some arbitrary power of the optical field or saturates at high powers. The effect of such non-Kerr-like nonlinearities on the power-dependent wave vector and field distributions is given for a number of potential devices proposed earlier for Kerr-like media.
• Moloney, J. V. (1984). Coexistent attractors and new periodic cycles in a bistable ring cavity. Optics Communications, 48(6), 435-438.
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  Abstract: Two distinct period doubling routes to chaos on the low transmission branch of a bistable ring cavity are identified with bifurcations from stable solutions in different regions of parameter space. New periodic cycles, which cannot be predicted by conventional linear stability analysis, can abruptly appear via a tangent bifurcation and undergo a period doubling cascade over a limited parameter range before disappearing. © 1984.
• Moloney, J. V. (1984). Self-Focusing-Induced Optical Turbulence. Physical Review Letters, 53(6), 556-559.
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  Abstract: Transverse outputs of an optical resonator are predicted to undergo transitions to turbulence via three well-established scenarios. The instabilities are induced by self-focusing nonlinearities. A bifurcation involving period doubling of invariant circles in a parameter region where attractors coexist is identified. © 1984 The American Physical Society.
• Faisal, F. H., & Moloney, J. V. (1983). Erratum: Time-dependent theory of non-hermitian schrödinger equation: Application to multiphoton-induced ionisation decay of atoms (Journal of Physics B: Atomic and Molecular Physics (1981) 14 (3603-20)). Journal of Physics B: Atomic and Molecular Physics, 16(16), 3109-.
• Gibbs, H. M., Jewell, J. L., Moloney, J. V., Tai, K., Tarng, S. S., Weinberger, D. A., Gossard, A. C., McCall, S. L., Passner, A., & Weigmann, W. (1983). OPTICAL BISTABILITY, REGENERATIVE PULSATIONS, AND TRANSVERSE EFFECTS IN ROOM-TEMPERATURE GaAs-AlGaAs SUPERLATTICE ETALONS.. Journal de Physique (Paris), Colloque, 44(3), 195-204.
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  Abstract: The quantum wells provided by a superlattice increase the binding energy of free excitons in GaAs, permitting 300 K bistable operation. Thermal and excitonic refractive index effects compete, resulting in regenerative pulsations. Transverse observations and simulations provide other interesting effects.
• Mc Laughlin, D., Moloney, J., & Newell, A. (1983). Solitary waves as fixed points of infinite-dimensional maps in an optical bistable ring cavity. Physical review letters, 51(2), 75.
• Moloney, J. V., III, M. S., & Gibbs, H. M. (1983). Transverse effects in absorptive optical bistability. Optics Communications, 44(4), 289-292.
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  Abstract: Absorptive bistability loops are computed for a laser beam with a gaussian input spatial profile incident on a unidirectional ring cavity containing a saturable nonlinear medium. Sharp radially dependent switching with wide bistable loops is predicted for large Fresnel numbers. Intermediate Fresnel numbers result in whole beam switching with significant narrowing of the associated bistable loops. At low Fresnel numbers, bistability can disappear. Radially integrated hysteresis loops differ quantitatively from plane-wave predictions. © 1983.
• Arecchi, F. T., Giusfredi, G., Petriella, E., Salieri, P., Giacobino, E., Cribier, S., Grynberg, G., Biraben, F., Gibbs, H. M., Jewell, J. L., Moloney, J. V., Rushford, M. C., Tai, K., Tarng, S. S., Weinberger, D. A., Gossard, A. C., McCall, S. L., Passner, A., Wiegmann, W., , Martinot, P., et al. (1982). Dynamical nonlinear optics and bistability. Applied Physics B Photophysics and Laser Chemistry, 29(3), 169-175.
• Miller, A., Miller, D. A., Bensoussan, M., Moison, J. M., Haueisen, D. C., Depatie, D. A., Kruse, P. W., Khan, M. A., Smirl, A. L., Wherrett, B. S., Boggess, T. F., Perryman, G. P., Chemla, D. S., Smith, P. W., Gossard, A. C., Tsang, W. T., Chu, S., Hu, P., Jedju, T. M., , Yuen, S. Y., et al. (1982). Dynamical NL optics, bistability. Applied Physics B Photophysics and Laser Chemistry, 28(2-3), 92-101.
• Moloney, J. (1982). Bistable Behaviour of a Detuned Fabry-Perot Etalon with a Gaussian input Spatial Profile under Self-focusing and Defocusing Conditions. Optica Acta: International Journal of Optics, 29(11), 1503-1508. doi:10.1080/713820780
• Moloney, J. V., & Gibbs, H. M. (1982). Role of Diffractive Coupling and Self-Focusing or Defocusing in the Dynamical Switching of a Bistable Optical Cavity. Physical Review Letters, 48(23), 1607-1610.
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  Abstract: Optical bistability transients have been computed including one transverse Cartesian coordinate. With a Gaussian transverse input profile but weak diffractive coupling, the switchup intensity is radially dependent, and the output requires hundreds of round trips to reach steady state. Strong diffractive coupling results in whole-beam switchup and much faster convergence to steady state. © 1982 The American Physical Society.
• Moloney, J. V., Belic, M. R., & Gibbs, H. M. (1982). Calculation of transverse effects in optical bistability using fast Fourier transform techniques. Optics Communications, 41(5), 379-382.
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  Abstract: The bistable system consists of a unidirectional ring cavity containing off-resonance saturable two-level atoms. Fourier transform techniques permit an efficient solution of the free-space and medium propagation equations. Dynamic outputs showing critical slowing down and overshoot switching explicitly display the role of diffractive coupling in a bistable device. © 1982.
• Moloney, J. V., Hopf, F. A., & Gibbs, H. M. (1982). Effects of transverse beam variation on bifurcations in an intrinsic bistable ring cavity. Physical Review A, 25(6), 3442-3445.
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  Abstract: Instabilities associated with bistable branches of positive differential gain are investigated numerically in a ring-cavity bistable device, allowing for transverse variation of the laser beam. Additional instability domains beyond those predicted by plane-wave analysis are shown to occur. The nature of the bifurcation sequences within each domain is different from the plane-wave case and is characterized by quasiperiodic and frequency-locked behavior. Some sequences are very similar to experimentally observed bifurcations in hydrodynamics. © 1982 The American Physical Society.
• Tai, K., Gibbs, H. M., & Moloney, J. V. (1982). Intracavity phase switching and phase-plane dynamics of a bistable optical device. Optics Communications, 43(4), 297-302.
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  Abstract: Since the field inside an optical cavity is a complex quantity, analysis in the phase plane gives a deeper insight into its time evolution. This was emphasized by the findings of Hopf and Meystre. We have extended their numerical analysis to include the possibility of Ikeda instabilities, showing that parameters can be selected that avoid Ikeda instabilities but permit intracavity phase switching. Switching, both up and down, can always be accomplished by applying an external pulse which changes the cavity detuning for an appropriate number of round trips. Inclusion of diffraction effects in one transverse dimension does not prevent switching. Clear, preset, and flip-flop operations, analogous to electronic operations, can also be achieved by properly choosing the external control pulses. © 1982.
• Tai, K., Moloney, J. V., & Gibbs, H. M. (1982). Optical cross talk between nearby optical bistable devices on the same etalon. Optics Letters, 7(9), 429-431.
• Faisal, F. H., & Moloney, J. V. (1981). Time-dependent theory of non-Hermitian Schrodinger equation: Application to multiphoton-induced ionisation decay of atoms. Journal of Physics B: Atomic and Molecular Physics, 14(19), 3603-3620.
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  Abstract: A rigorous and practical time-dependent formulation of quantum decay processes is obtained by converting the Hermitian Schrodinger problem into an equivalent non-Hermitian Schrodinger equation. The properties of the original Hermitian and the reduced non-Hermitian Hamiltonians are compared and the non-Hermitian formulation is shown to be consistent with the theorem of Fock and Krylov for the description of truly decaying states. A self-consistent non-unitary algorithm is developed and used to obtain expressions for the time-dependent transition amplitudes of interest; they automatically preserve the total probability in the sum space at all future times tau >0. The formalism is coded for application to the important problem of ionisation decay of a ground-state hydrogen atom coupled to a strong radiation field with a sub-threshold photon frequency. The first quantitative information on the time dependence of two- and three-photon (resonant and non-resonant) ionisation of the hydrogen atom is obtained.
• Moloney, J. V., & Faisal, F. H. (1980). Propagation of a gaussian pulse under two-photon near-resonant conditions. Journal of Physics B: Atomic and Molecular Physics, 13(10), 2137-2146.
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  Abstract: Evolution under two-photon near-resonance conditions of an adiabatic Gaussian pulse is considered in Rb vapour. Theoretical results show strong self-phase modulation and pulse deformation with increasing distance of propagation and intensity at a fixed detuning. At sufficiently large distances of propagation and/or input intensity pulse deformation is seen to develop into (two-photon) optical shocks. At a higher intensity double shock fronts are predicted to occur. The previously anticipated existence of an upper bound for the output maximum and of the vanishing of the self-phase modulation at the 'interaction time' between the output and the input profiles are shown explicitly to hold for the cases considered. A quasi free-wave like evolution occurs at asymptotically higher intensities.
• Moloney, J. V., & Faisal, F. H. (1979). Computation of multiphoton IR spectra of small molecules: Application to CO. Journal of Physics B: Atomic and Molecular Physics, 12(17), 2829-2840.
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  Abstract: A non-perturbative theoretical method has been generalised to compute rovibrational multiphoton excitation probabilities in small molecules. The practicability of the method is illustrated by direct computation for CO. Novel non-linear features emerge in the absorption spectrum when the power broadening of individual rovibrational lines becomes comparable to the rotational constant of the molecule. The results also establish that over-simplified N-level models should be treated with caution.
• Moloney, J. V., & Faisal, F. H. (1979). Possibility of directly observing Autler-Townes power splitting of certain rotational lines with an intense ir laser. Optics Communications, 29(1), 62-66.
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  Abstract: The possibility of simultaneous induction and detection, with an intense single mode ir laser, of the Autler Townes splittings of certain rovibrational lines in diatomics is discussed. A model based on the accurately known molecular parameters and dipole matrix elements of CO is used to exhibit the power splitting effect for the case of two quantum excitation. The power splitting effect, which exhibits a threshold as a function of laser intensity is clearly discernable in both the two and one quantum absorption profiles as well as in the total absorption spectrum. Using a simple qualitative rule we predict that such rovibrational line splittings should also be observable in an analogous set of transitions in other diatomics. © 1979.
• Moloney, J. V., & Meath, W. J. (1978). Induced transition probabilities and energies for the strongly coupled two-level system. Physical Review A, 17(4), 1550-1554.
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  Abstract: An exact method of solution to the time-dependent wave equation for a system interacting with a sinusoidal field, which formally treats time and the phase of the field on an equal footing, is used to discuss (1) the importance of averaging the properties of a system over the phase of the applied field and (2) the nature and behavior of the characteristic exponents derived from the Floquet solution (with particular emphasis on the frequency-sweep experiment). The results for the Zeeman tuning experiment are used to resolve recent discrepancies in the literature which relate to the validity of Shirley's important result for the two-level average induced transition probability involving the derivative of the characteristic exponents with respect to the Zeeman splitting parameter ω0. The explicit calculations included in this work are for the single-photon two-level problem. Important implications can be inferred from them with respect to both the importance of phase averaging and the usefulness of the characteristic exponents as a quantitative means of obtaining resonance frequency shifts and half-widths for multiphoton and multilevel problems. © 1978 The American Physical Society.
• Moloney, J. V., & Meath, W. J. (1978). Multi-photon spectra in the presence of strongly saturating oscillating and static fields. Molecular Physics, 35(4), 1163-1175. doi:10.1080/00268977800100841
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  A solution for the time-dependent Schrodinger equation is given for an N-level system interacting with a sinusoidal field of arbitrary amplitude , frequency v and phase δ, in the presence of an applied static field of arbitrary strength . The solution is obtained by a modification of a previous exact method of solution for and retains the essential analytic features of the exact wavefunction for the problem. The Floquet form of the solution yields (a) the location and the widths of allowed transitions and the location of forbidden transitions, by use of characteristic exponent plots, but without evaluating the spectrum, and (b) convenient expressions for the steady-state induced transition probabilities, including the effects of a uniform relaxation mechanism, that only require the solution of the wave equation over the initial period of the hamiltonian. The approach is equally applicable to Stark (or Zeeman) frequency sweep or tuning problems. The ability to incorporate the effects of static fields in th...
• Moloney, J. V., & Meath, W. J. (1978). Non-linear resonance frequency shifts and saturation effects by oscillating and static applied fields in multi-level systems. Journal of Physics B: Atomic and Molecular Physics, 11(15), 2641-2653.
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  Abstract: A previously developed exact semiclassical method is used to evaluate multi-photon spectra and Floquet characteristic exponents (dressed-atom energies) for several multi-level systems interacting with both strong oscillating and static fields under varying degrees of saturation. The usefulness of characteristic exponent plots in extracting the physically significant features of the spectrum, without the necessity of evaluating portions of the complete spectrum, is demonstrated for a number of model three-level systems which are not directly amenable to study by the often used rotating-wave approximation. The effect of neighbouring non-resonant states on two-photon resonance profiles is also discussed using three to six level systems (H and Na atoms) as models.
• Moloney, J. V., & Meath, W. J. (1976). Phase and temporal average transition probabilities for a multi-level system in a sinusoidal field. Molecular Physics, 31(5), 1537-1548. doi:10.1080/00268977600101211
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  A previous exact formal and practical solution for the time-dependent Schrodinger equation for a two-level non-degenerate system in an arbitrarily strong sinusoidal field is transformed for an N-level system to a Floquet form. Using the Floquet form of the solution computationally convenient expressions are obtained for the phase and the phase-long time-averaged induced transition probabilities. The method exploits the time periodicity of the Schrodinger equation and the solution over the initial period of the hamiltonian provides all the information needed to obtain both the unaveraged and the averaged transition probabilities for the system. The method is illustrated by specific examples which are used to discuss some of the temporal features of the multi-photon spectra of two-level systems.
• Moloney, J. V., & Meath, W. J. (1975). Time dependence of a two-level system for arbitrary sinusoidal field strengths and times. Molecular Physics, 30(1), 171-178. doi:10.1080/00268977500101851
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  An exact formal and practical solution for the time-dependent Schrodinger equation is given for a two-level system in an arbitrarily strong sinusoidal field. The periodicity of the time-dependent wave equation is fully exploited and the solution over the initial period of the wave equation essentially provides the complete solution for arbitrarily long times. The solution over the initial time period is generated by using a previously derived power series technique. The method is illustrated by explicit examples.
• Moloney, J. V., Ali, M. K., & Meath, W. J. (1974). Time dependence of a two-level system in a sinusoidal field☆. Physics Letters A, 49(3), 207-208. doi:10.1016/0375-9601(74)90852-4
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  Abstract An iterative step-wise power series solution for the time dependent Schrodinger equation is presented for a two level system in a sinusoidal external field.

Proceedings Publications

• Gibson Jr, ,., Tsaoussis, S. P., Rollag, J., Nguyen, C., Follman, D., Cole, G. D., Addamane, S., Moloney, J. V., & Jones, R. J. (2023). Hybrid SESAMs for high-repetition rate mode-locked VECSELs. In Vertical External Cavity Surface Emitting Lasers (VECSELs) XII, 12404.
• Hader, J., Dineen, C., & Moloney, J. V. (2023). Optical Properties of 2D Nonlinear Functional Materials. In 2023 IEEE Research and Applications of Photonics in Defense Conference (RAPID).
• Hader, J., Liebscher, S. C., Moloney, J. V., & Koch, S. W. (2023). Microscopic analysis of linear and nonlinear electro-optical properties of tellurium. In Nonlinear Frequency Generation and Conversion: Materials and Devices XXII, 12405.
• Hader, J., Neuhaus, J., Moloney, J. V., & Koch, S. W. (2023). Influence of Coulomb correlations on high harmonic generation in monolayer TMDCs. In 2D Photonic Materials and Devices VI, 12423.
• Hader, J., Neuhaus, J., Moloney, J. V., & Koch, S. W. (2023). Influence of Excitonic Correlations on the High Harmonic Generation in Monolayer TMDCs. In CLEO: Fundamental Science.
• Han, A., Dineen, C., Islam, M. S., Moloney, J. V., & Babicheva, V. E. (2023). Symmetry breaking and second-harmonic generation in plasmonic nanoparticle arrays. In Nonlinear Optics.
• Hastings, M. G., Panagiotopoulos, P., Kolesik, M., & Moloney, J. V. (2023). The existence of multi-octave spanning conical emission from ultrafast LWIR pulse filamentation. In Nonlinear Frequency Generation and Conversion: Materials and Devices XXII, 12405.
• Rudenko, A., Han, A., Hagen, M. K., Hader, J., Kruk, S., Kivshar, Y., Koch, S. W., & Moloney, J. V. (2023). Modeling of low-and high-order harmonic generation in ultrashort laser-excited resonant semiconductor nanostructures. In Ultrafast Phenomena and Nanophotonics XXVII, 12419.
• Tsaoussis, S. P., Addamane, S., Jones, R. J., & Moloney, J. V. (2023). Coupled mode-locked VECSEL cavities with a shared gain medium. In Vertical External Cavity Surface Emitting Lasers (VECSELs) XII, 12404.
• Tsaoussis, S. P., Gibson, R., Rollag, J., Nguyen, C., Follman, D., Cole, G., Addamane, S., Moloney, J. V., & Jones, R. J. (2023). Hybrid SESAM Mode-Locked VECSEL. In CLEO: Science and Innovations.
• Moloney, J. V. (2022). A. Rudenko, M. K. Hagen, J. Hader, M. Kolesik, S. W. Koch, and J. V. Moloney, "Maxwell-semiconductor Bloch simulations of high-harmonic generation in finite thickness semiconductor slabs", SPIE, vol. 11999, pp. 56--61 (2022). In Ultrafast Phenomena and Nanophotonics XXVI, 11999, 119990A.
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  A. Rudenko, M. K. Hagen, J. Hader, M. Kolesik, S. W. Koch, and J. V. Moloney, "Maxwell-semiconductor Bloch simulations of high-harmonic generation in finite thickness semiconductor slabs", SPIE, vol. 11999, pp. 56--61 (2022)
• Moloney, J. V. (2022). Influence of inter- and intra-valley carrier dynamics on the optical properties of monolayer TMDCs. In Proc. SPIE 12003, 2D Photonic Materials and Devices V, 12003, 1200303.
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  J. Hader, J.V. Moloney, J. Neuhaus, and S.W. Koch, "Influence of inter- and intra-valley carrier dynamics on the optical properties of monolayer TMDCs," Proc. SPIE 12003, 2D Photonic Materials and Devices V; 1200303 (2022)
• Moloney, J. V. (2022). Influence of inter-and intra-valley carrier dynamics on the optical properties of monolayer. In SPIE.
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  J. Hader, J. V. Moloney, J. Neuhaus, and S. W. Koch “Influence of inter-and intra-valley carrier dynamics on the optical properties of monolayer” TMDCs. In 2D Photonic Materials and Devices V (Vol. 12003, pp. 8-14).
• Bondaz, T. A., Laurain, A., Moloney, J. V., & Mcinerney, J. G. (2020). Generation and stabilization of continuous wave THz emission from a bi-color VECSEL. In Vertical External Cavity Surface Emitting Lasers (VECSELs) X, 11263.
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  We present a laser system for the generation and stabilization of continuous wave emission at 1.9 THz. The system is based on difference frequency generation (DFG) from a bi-color vertical external cavity surface emitting laser (VECSEL). The intracavity DFG process enables THz generation with milliwatt power level at room temperature with a clear quadratic dependence on the intracavity power. The two colors are spectrally selected via an intracavity etalon while the laser cavity geometry is engineered to minimize mode competition between the two colors via spatial hole burning, improving the stability of the THz emission. The intensity noise of the THz output is further reduced by 16 dB/Hz with an active stabilization scheme. The origin of residual fluctuations is discussed and we found that the asymmetrical amplification of one color reduced the RIN even further, down to 21 dB/Hz, comparing to the free-running symmetrical lasing.
• Hader, J., Moloney, J. V., Meckbach, L., Stroucken, T., & Koch, S. W. (2019). Carrier dynamics in TMDCs for optical applications. In 2D Photonic Materials and Devices II, 10920.
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  Fully microscopic many-body models based on the Dirac-Bloch equations and quantum-Boltzmann type scattering equations are used to study the carrier dynamics in monolayer transition metal dichalcogenides (TMDCs) under conditions as typical for applications as lasers, diodes or saturable absorbers. The carrier-carrier scattering is shown to be happening on an ultra-fast few-femtosecond timescale for excitations high above the bandgap. Once the carriers have relaxed into quasi-equilibrium distributions near the bandgap, the scattering is slowed dramatically by phase-space filling and screening of the Coulomb interaction. Here, the scatterings and resulting dephasing of the optical polarizations happen on a 100fs timescale and lead to similar broadenings as found in conventional III-V semiconductor materials. Also like the case in III-V materials, the carrier phonon scattering times are found to be in the picosecond range. The scatterings are shown to allow for gain spectra as needed for good lasing operation. It is shown that the weak interaction between the two bands associated with the two different sub-lattices can potentially allow for simultaneous lasing at two different frequencies. Strong absorption and ultrafast carrier relaxation could allow for TMDCs to be used in saturable absorption applications.
• Kilen, I. R., Hader, J., Koch, S. W., & Moloney, J. V. (2019). Influence of microscopic many-body scattering on multi-wavelength VECSEL lasing. In Vertical External Cavity Surface Emitting Lasers (VECSELs) IX, 10901.
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  Non-equilibrium multi-wavelength operation of vertical external-cavity surface-emitting lasers (VECSELs) is investigated numerically using a coupled system of Maxwell semiconductor Bloch equations. The propagation of the electromagnetic field is modeled using Maxwell’s equations, and the semiconductor Bloch equations simulate the optically active quantum wells. Microscopic many-body carrier-carrier and carrier-phonon scattering are treated at the level of second Born-Markov approximation, polarization dephasing with a characteristic rate, and carrier screening with the static Lindhard formula. At first, an initialization scheme is constructed to study multi-wavelength operation in a time-resolved VECSEL. Intracavity dual-wavelength THz stabilization is examined using longitudinal modes and an intracavity etalon. In the latter, anti-correlated noise is observed for THz generation and investigated.
• Moloney, J. V. (2018). High Brightness, Low Noise CW and GHz Repetition Rate Mode-Locked Semiconductor Disk Lasers. In 2018 IEEE International Semiconductor Laser Conference (ISLC).
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  Optically-pumped semiconductor disk (vertical external cavity) lasers offer marked advantages over high power edge emitters. They offer high brightness, high noise suppression, no facet damage, multiple tens of Watt CW TEM00 single frequency, narrow line emission and enormous flexibility in intra-cavity tunable SHG and DFG high efficiency sources. Optically-pumped semiconductor disk lasers (OPSLs), also referred to as vertical external-cavity semiconductor lasers (VECSELs), offer enormous flexibility in their compact cavity design, excellent TEM00 beam quality as single frequency multiple tens of Watts wavelength agile sources and high brightness raw power sources with demonstrated power exceeding 100 Watts from a single emitter. At the latter power levels, there is evidence for strong lateral ASE and lasing when the spot size exceeds 1 millimeter. The compact cavity arrangement facilitates high power intra-cavity SHG generation in the visible and UV and OPSL technology now underlies Coherent's main product line of commercial semiconductor laser sources. The high circulating intra-cavity powers have also enabled the demonstration of record high power room temperature tunable THz emission via intra-cavity DFG. High peak and average power mode-locking has been demonstrated when a saturable semiconductor absorber mirror (SESAM) is inserted in the cavity. The short cavity lengths provide for high repetition rates in the 1–10 GHz range and such sources are currently being investigated as seed sources for frequency comb generation. Current challenges lie in SESAM degradation that becomes evident when pulse durations decrease towards 100 fs and peak power densities reach the multi-kW range. The current short pulse record is 95 fs. Different SESAM growth methodologies are being investigated including ultrafast surface state recombination of a near surface grown QW, low temperature QW growth, graphene and other saturable absorber sources.
• Boettge, C. N., Hader, J., Kilen, I., Koch, S. W., Moloney, J. V., & Guina, M. (2015, 2015). Influence of non-equilibrium carrier dynamics on pulse amplification in semiconductor gain media. In VERTICAL EXTERNAL CAVITY SURFACE EMITTING LASERS (VECSELS) V, 9349.
• Klien, I., Boettge, C. N., Hader, J., Koch, S. W., Moloney, J. V., & Guina, M. (2015, 2015). Ultrafast non-equilibrium carrier dynamics in semiconductor laser mode-locking. In VERTICAL EXTERNAL CAVITY SURFACE EMITTING LASERS (VECSELS) V, 9349.
• Scheller, M., Baker, C. W., Gbele, K., Koch, S. W., Jones, R. J., Moloney, J. V., & Guina, M. (2015, 2015). Ultrafast in-situ probing of passively mode-locked VECSEL dynamics. In VERTICAL EXTERNAL CAVITY SURFACE EMITTING LASERS (VECSELS) V, 9349.
• Born, N., Scheller, M., Moloney, J. V., & Koch, M. (2014). Cavity enhanced modulation of sharp THz bands. In 2014 39th International Conference on Infrared, Millimeter, and Terahertz waves (IRMMW-THz), 1-2.
• Scheller, M., Paul, J. R., Laurain, A., Young, A., Koch, S. W., & Moloney, J. V. (2014). Single-frequency terahertz source based on difference frequency generation in an enhancement cavity. In 2014 39th International Conference on Infrared, Millimeter, and Terahertz waves (IRMMW-THz), 1-2.
• Albrecht, A. R., Seletskiy, D. V., Cederberg, J. G., Di Lieto, A., Tonelli, M., Moloney, J. V., Balakrishnan, G., & Sheik-Bahae, M. (2012). Intracavity laser cooling using a VECSEL. In SPIE OPTO, 827505--827505.
• Hessenius, C., Guinet, P. Y., Lukowski, M., Moloney, J., & Fallahi, M. (2012). 589-nm single-frequency VECSEL for sodium guidestar applications. In SPIE LASE, 82420E--82420E.
• Laurain, A., Hader, J., Lai, Y., Wang, T., Yarborough, M., Balakrishnan, G., Rotter, T. J., Ahirwar, P., & Moloney, J. V. (2012). Influence of non-radiative carrier losses on pulsed and continuous VECSEL performance. In SPIE LASE, 82420S--82420S.
• Wichmann, M., Chernikov, A., Shakfa, M. K., Koch, S. W., Scheller, M., Moloney, J. V., & Koch, M. (2012). Study of the two-color emission dynamics from a vertical-external-cavity surface-emitting laser. In 2012 37th International Conference on Infrared, Millimeter, and Terahertz Waves, 1-3.
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  We present a systematic study on the time dynamics of the two-color emission from a vertical-external-cavity surface-emitting laser. By using a streak camera, time- and frequencyresolved images of the VECSEL emission are acquired. Stable and unstable regimes are identified via a statistical analysis. Furthermore, the influence of additional intracavity losses on the two-color emission is investigated.
• Hader, J., Moloney, J. V., & Koch, S. W. (2011). Density-activated defect recombination as a possible explanation for the efficiency droop in GaN-based light emitters. In 2011 Conference on Lasers and Electro-Optics Europe and 12th European Quantum Electronics Conference (CLEO EUROPE/EQEC), 1-1.
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  The droop of the internal efficiency in GaN-based light emitting devices reflects a carrier loss mechanism that has a stronger dependence on the intrinsic carrier density than the about quadratic dependence of the radiative recombinations. Here we discuss density-activated defect recombination (DADR) [1] as a possible source for this non-radiative loss - at least for the low to medium density regime.
• Zeng, Y., Hoyer, W., Liu, J., Koch, S. W., & Moloney, J. V. (2009). A Classical Study of Second-Harmonic Generation from Metallic Nanoparticles. In Advances in Optical Sciences Congress.
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  We developed a classical electrodynamics theory to study the optical nonlinearities of metallic nanoparticles. Through a detailed comparison between existing experiments and numerical simulations, we validated this theory as well as the associated numerical algorithm.
• Li, L., Sch\"ulzgen, A., Temyanko, V. L., Spiegelberg, C., Nguyen, D. T., Zhu, X., Moloney, J. V., Albert, J., & Peyghambarian, N. (2008). Cladding-pumped distributed feedback phosphate glass fiber lasers. In Conference on Lasers and Electro-Optics, CMA1.
• Moloney, J. V., Hader, J., Fan, L., Fallahi, M., Koch, S. W., & Stolz, W. (2007). Closed-loop design of a semiconductor laser. In SPIE Proceedings, 6475.
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  We present an overview of a novel first principles quantum approach to designing and optimizing semiconductor QW material systems for target wavelengths. Using these microscopic inputs as basic building blocks we predict the L-I characteristic for a low power InGaPAs ridge laser without having to use adjustable fit parameters. Finally we employ these microscopic inputs to develop sophisticated simulation capabilities for designing and optimizing end packaged high power laser structures. As an explicit example of the latter, we consider the design and experimental demonstration of a vertical external cavity semiconductor laser (VECSEL).
• Klein, M. W., Enkrich, C., Wegener, M., Forstner, J., Moloney, J. V., Hoyer, W., Stroucken, T., Meier, T., Koch, S. W., & Linden, S. (2006). Optical Experiments on Second-Harmonic Generation with Metamaterials Composed of Split-Ring Resonators. In Photonic Metamaterials: From Random to Periodic.
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  We study optical second-harmonic generation from planar arrays of magnetic split-ring resonators at 1.5 microns resonance wavelength. We obtain by far the largest signals when exciting the magnetic-dipole resonance.
• Klein, M. W., Enkrich, C., Wegener, M., Forstner, J., Moloney, J. V., Hoyer, W., Stroucken, T., Meier, T., Koch, S. W., & Linden, S. (2006). Optical experiments on second-harmonic generation from metamaterials consisting of split-ring resonators. In 2006 Conference on Lasers and Electro-Optics and 2006 Quantum Electronics and Laser Science Conference, 1-2.
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  We discuss second-harmonic generation experiments on planar arrays of magnetic split-ring resonators, using 150 fs pulses at 1.5 mum wavelength. Lithographic tuning reveals by far the largest signals when exciting the magnetic-dipole resonance.
• Bedford, R., Kolesik, M., Chilla, J., Reed, M., Nelson, T., & Moloney, J. (2005). Power-limiting mechanisms in VECSELs. In Defense and Security, 199--208.
• Schlichenmaier, C., Thranhardt, A., Meier, T., Gruning, H., Klar, P. J., Heimbrodt, W., Koch, S. W., Chow, W. W., Hader, J., & Moloney, J. V. (2005). Analysis of dilute nitride semiconductor laser gain materials in the 1.3-1.5 /spl mu/m range. In 2005 Quantum Electronics and Laser Science Conference, 2, 1053-1055.
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  Theory/experiment comparisons of optical properties of dilute nitride heterostructures are presented. A type I - type II transition in In/sub 0.23/Ga/sub 0.77/As/GaN/sub x/As/sub 1-x/ heterostructures is identified. The model is used for a study of lasing in the 1.3-1.5 /spl mu/m range.
• Hader, J., Zakharian, A. R., Moloney, J. V., Nelson, T. R., Ehret, J. E., Koch, S. W., & Nelson, J. T. (2003). Gain and luminescence modeling for high power laser applications. In SPIE Proceedings, 4993, 99-103.
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  A general scheme for the determination of vital operating characteristics of semiconductor lasers from low intensity photo-luminescence spectra is outlined and demonstrated. A fully microscopic model for the optical properties is coupled to a drift-diffusion model for the mesoscopic charge and field distributions to calculate luminescence and gain spectra in barrier-doped laser material. Analyzing experiments on an optically pumped multi quantum-well structure it is shown that the electric fields arising from the charges of ionized dopants lead to strongly excitation dependent optical properties like significant differences between luminescence and gain wavelengths.
• Heller, E. K., Scarmozzino, R., Hader, J., Moloney, J. V., Koch, S. W., & Grote, B. H. (2003). Integration of microscopic gain modeling into a commercial laser simulation environment. In SPIE Proceedings, 4986, 413-422.
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  We demonstrate the integration of microscopic gain calculation into the laser design tool LaserMOD, which is derived from the Minilase II simulator. A microscopic many body theory of the semiconductor allows for the accurate modeling of the spectral characteristics of the material gain. With such a model, the energetic position of the gain peak, the collision broadening, and therefore, the absolute magnitude of the gain can be predicted based solely on material parameters [2]. In contrast, many simpler approaches rely on careful calibration of model parameters requiring additional effort due to fabrication of samples and experimental studies. In our full scale laser simulation multi dimensional carrier transport, interaction with the optical field via stimulated and spontaneous emission, as well as the optical field itself is computed self consistently. We demonstrate our approach on an example of a Fabry-Perot laser structure with GaInAsP multiple quantum wells for 1.55 μm emission wavelength.
• Kouznetsov, D., & Moloney, J. V. (2003). Highly efficient incoherent slab-pumped fiber amplifier/laser designs. In SPIE Proceedings, 4993, 111-119.
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  The problem of delivering a multimode pump to a single mode core is considered. Original designs of double-clad fiber amplifiers are analyzed. A slab pump geometry of a fiber amplifier is suggested. The partially coherent pump should be coupled to the narrow slab which supports propagation of the pump and absorbs highest modes of the core, then the core itself has no need to be single-mode. The slab plays the role of cladding in conventional double-clad fibers. Such a cladding has no need to surround the core and its refractive index can be higher than that of the core. Then the highest modes of the slab are absorbed at the very beginning of the amplifier. This allows for tapering of the slab, providing almost constant pump power in the core. The end result is a the high efficiency of a compact device with scaling to high pump power. We provide the key design formulars for such a device.
• Rossler, T., Moloney, J. V., & Ackemann, T. (2003). A vectorial model for transverse mode selection in vertical-cavity surface-emitting lasers. In 5th International Workshop on Laser and Fiber-Optical Networks Modeling, 2003. Proceedings of LFNM 2003., 293-295.
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  Due to their large Fresnel number, broad-area vertical-cavity surface-emitting lasers (VCSELs) show a strong tendency for emission with a very complex spatial and spectral structure . On the one hand side the resulting reduction in spatial and temporal coherence is detrimental for applications and hence a thorough understanding of these instabilities is sought for. On the other hand, these phenomena make VCSELs very interesting for studying spatial self-organization in quasi two-dimensional laser systems. The model incorporates also the vectorial degrees of freedom of the active quantum well medium as well as of the light field. This is motivated by the intriguing experimental results.
• Hader, J., Koch, S. W., Zakharian, A. R., Moloney, J. V., Ehret, J. E., Nelson, T. R., & Nelson, J. T. (2002). Gain and photoluminescence in semiconductor lasers. In SPIE Proceedings, 4646, 251-257.
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  A general scheme for the determination of vital operating characteristics of semiconductor lasers from low intensity photo-luminescence spectra is outlined and demonstrated. A fully microscopic model for the calculation of optical properties is coupled to a drift diffusion model for the mesoscopic charge and electric field distributions to calculate photo-luminescence and gain spectra in barrier-doped semiconductor laser material. Analyzing experiments on an optically pumped multi quantum-well structure it is demonstrated that the electric fields arising from the space charges of ionized dopants contribute to strongly excitation dependent optical properties, such as significant shifts of the luminescence versus peak gain wavelengths.
• Hader, J., Moloney, J. V., & Koch, S. W. (2002). Carrier capture times in 1.3-μm materials: GaInNAs, InGaAsP, and InGaAlAs semiconductor quantum well lasers. In SPIE Proceedings, 4646, 287-292.
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  A fully microscopic model is used to calculate the carrier capture times in quantum-well lasers operating at wavelengths in the 1.3 micrometers regime. The capture times are shown to be crucially dependent on the carrier confinement and therefore on the well and barrier materials. For a common well width of 6nm the capture times in InP/InGaAlAs and InP/InGaAsP structures are found to be in the 5ps range, whereas about a factor of ten longer times are predicted in GaInNAs/GaAs. By lowering the barriers using GaInNAs instead of pure GaAs or widening the well capture times similar to those in the InP-based structures can be obtained in the GaInNAs-based structures.
• White, J. K., Joshi, A., Extavour, M., Springthorpe, A. J., Hader, J., Moloney, J. V., & Koch, S. W. (2002). Superlattice physics of digitally grown epitaxial InAlGaAs layers. In SPIE Proceedings, 4646, 271-278.
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  The material physics of digitally grown InAlGaAs quaternary alloy systems are investigated using Molecular Beam Epitaxy (MBE) grown layers. With MBE, arbitrary epitaxial alloy compositions can be achieved, without changing the group III elemental constituents flux rates, by simple sequential shuttering of the relevant fluxes. Monolayer fluctuations create inhomogeneities that lead to a broadening of the photoluminescence (PL) spectra. Multiple PL peaks are also seen in select alloy compositions.
• Kent, A. J., Huyet, G., Mcinerney, J. G., White, J. K., Moloney, J. V., Porta, P. A., & Hegarty, S. P. (1998). A Multimode Model for the Dynamics of a Semiconductor Laser with Optical Feedback. In CLEO/Europe Conference on Lasers and Electro-Optics, 282-282.
• Ru, P., Chow, W. W., Moloney, J. V., & Koch, S. W. (1994). Quantum confinement and strain effects in an unstable resonator semiconductor laser. In Physics and Simulation of Optoelectronic Devices II, 2146, 427-432.
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  A physical optics laser model based on a many-body semiclassical laser theory of the gain medium is used to investigate the gain medium effects on the modal stability of an unstable resonator semiconductor laser. Quantum confinement or strain are shown to result in single-mode operation over significantly wider ranges of unstable resonator configurations and gain medium excitation.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
• Ehrlich, J., Adachihara, H., Valera, J., Moloney, J., & Walker, A. (1991). Two-photon absorption and self-defacusing in Poly 4-BCMU waveguides. In Quantum Electronics and Laser Science Conference, QTuI29.

Presentations

• Moloney, J. V. (2022). Extreme Nonlinear Optics in Semiconductors. NTNU Faculty of Natural Sciences and Technology, Department of Physics, September 9, 2022.
• Moloney, J. V. (2022). Laser Pulse driven Fog Clearing, Nonlinear localization through turbulence and Extreme NLO in Dieletric/Plamonic Metasurfaces. The Arctic University of Norway, Tromso, September 7, 2022.
• Moloney, J. V. (2022). Laser Pulse driven Fog Clearing, Nonlinear localization through turbulence and Extreme NLO in Dieletric/Plamonic Metasurfaces. University College Cork, Ireland, September 12, 2022.
• Moloney, J. V. (2022). Maxwell-Semiconductor Bloch simulations of high-harmonic generation in finite thickness semiconductor slabs. Ultrafast Phenomena and Nanophotonics XXVI.
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  A. Rudenko, M. K. Hagen, J. Hader, M. Kolesik, S. W. Koch, and J. V. Moloney "Maxwell-Semiconductor Bloch simulations of high-harmonic generation in finite thickness semiconductor slabs"
• Moloney, J. V. (2022). Overview of theoretical and experimental ultrafast nonlinear optics in semiconductors. University College Cork, Ireland, June 3, 2022.
• Moloney, J. V. (2022). Overview of theoretical and experimental ultrafast nonlinear optics in semiconductors. University Marburg, Germany, June 10, 2022.
• Moloney, J. V. (2022). Semi-Classical Modeling of Hot Electron Spatio-Temporal Dynamics in Ultrashort Laser-Excited Plasmonic Nanostructures. Mutliscale Materials Modeling Conference (MMM10).
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  A. Rudenko, J.V. Moloney, "Semi-Classical Modeling of Hot Electron Spatio-Temporal Dynamics in Ultrashort Laser-Excited Plasmonic Nanostructures"
• Moloney, J. V. (2022). Simulations of long plasma channel generation in the atmosphere through mid-IR pulsed Bessel beams (A). Directed Energy Science and Technology Symposium (DEPS).
• Moloney, J. V. (2022). Ultrafast Resonant and Non-Resonant Nonequilibrium, Nonlinear Optical Interactions in Semiconductors. Global Summit and Expo on Lasers, Optics and Photonics (GSELOP), Edinburg, Scotland, August 2022.
• Moloney, J. V. (2021). Modeling of water droplet excitation and shattering by ultrashort long-wave infrared laser pulses for efficient fog clearing,. High Power Laser Ablation Symposium 2021 (HPLA).
• Moloney, J. V. (2021). Numerical simulations of the long-range energy delivery and beam breakup of high-power square-aperture CO2 laser pulses in the atmosphere. Directed Energy Science & Engineering Symposium 2021 (DEPS)DEPS.
• Moloney, J. V. (2021). Simulations of the Atmospheric Propagation of High Power 10.6-micron Square Frame Beams Generated by Unstable CO2 Resonators. High Power Laser Ablation 2021 (HPLA).
• Moloney, J. V. (2021). Simulations on the propagation dynamics of TW square-aperture CO2 laser pulses in the atmosphere. Conference on Lasers and Electro-Optics - CLEO 2021.

Poster Presentations

• Moloney, J. V. (2021). Filamentation-free Self-compression of LWIR Pulses in a CO2 Gas-filled Multi-pass Cell: A Numerical Study. Conference on Lasers and Electro-Optics - CLEO 2021.

Others

• Kolesik, M., Brown, J. M., Teleki, A., Jakobsen, P., Moloney, J. V., & Wright, E. M. (2015, MAY 20). Metastable electronic states and nonlinear response for high-intensity optical pulses (vol 1, pg 323, 2014). OPTICA.