Robert A Norwood
- Professor, Optical Sciences
- Member of the Graduate Faculty
Contact
- (520) 626-0936
- Meinel Optical Sciences, Rm. 533
- Tucson, AZ 85721
- rnorwood@optics.arizona.edu
Biography
obert A. Norwood is a Professor in the Wyant College of Optical Sciences at the University of Arizona, where he performs research on photonic materials and devices. Dr. Norwood spent 15 years in R&D leadership positions in industry at both Fortune 100 corporations (AlliedSignal now Honeywell) and venture-capital backed startups (VP/CTO of Photon-X). He founded Norcon Technologies in 2017 to commercialize novel hybrid chalcogenide optical polymers developed at the University of Arizona. He is a world expert in integrated photonics, nonlinear optics and optical materials, with more than 195 refereed publications, 7 book chapters, 46 issued US patents, and 90 invited talks. Dr. Norwood has served on the program committees for OFC (sub-committee chair) and CLEO. He has been an associate editor of Optica, IEEE Photonics Technology Letters and Optical Materials Express. Dr. Norwood is a Fellow of Optica, SPIE and the National Academy of Inventors, as well as a member of APS and IEEE. He holds the Ph.D. in physics from the University of Pennsylvania, and B.S.'s in physics and mathematics from MIT.Degrees
- Ph.D. Physics
- University of Pennsylvania, Philadelphia, Pennsylvania, United States
- Optical Kerr Effect Spectroscopy in Three Kerr Liquids
- B.S. Mathematics
- Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
- B.S. Physics
- Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
- Near Angle Scattering from Mirrors
Work Experience
- College of Optical Sciences, University of Arizona (2004 - Ongoing)
- Photon-X, Inc. (1999 - 2004)
- AlliedSignal (1995 - 1998)
- Hoechst Celanese (1988 - 1995)
Awards
- National Academy of Inventors Fellow
- National Academy of Inventors, Fall 2020
- Governor's Innovation Award - Academia
- Arizona Tech Council, Fall 2017
Interests
Teaching
Teaching interests include photonics, nonlinear photonics, advanced optics and photonics laboratories, innovation, modern optical physics, and electromagnetism among other areas.
Research
Research interests include integrated photonics, silicon photonics, optical polymers, infrared optical polymers, magneto-optic imaging, electro-optic modulators, solar energy systems, optical computing, nanophotonic circuits, optical sensing, and optical materials.
Courses
2024-25 Courses
-
Dissertation
OPTI 920 (Fall 2024) -
Independent Study
PHYS 599 (Fall 2024) -
Thin Film Optics and Photonics
OPTI 575 (Fall 2024)
2023-24 Courses
-
Directed Graduate Research
OPTI 792 (Spring 2024) -
Dissertation
OPTI 920 (Spring 2024) -
Independent Study
PHYS 599 (Spring 2024) -
Photonics Innovation to Market
ECE 539A (Spring 2024) -
Photonics Innovation to Market
OPTI 439A (Spring 2024) -
Photonics Innovation to Market
OPTI 539A (Spring 2024) -
Dissertation
OPTI 920 (Fall 2023) -
Independent Study
OPTI 599 (Fall 2023) -
Independent Study
PHYS 599 (Fall 2023) -
Nonlinear Photonics
OPTI 553 (Fall 2023)
2022-23 Courses
-
Dissertation
OPTI 920 (Spring 2023) -
Master's Report
OPTI 909 (Spring 2023) -
Photonics Innovation to Market
ECE 539A (Spring 2023) -
Photonics Innovation to Market
OPTI 439A (Spring 2023) -
Photonics Innovation to Market
OPTI 539A (Spring 2023) -
Thesis
OPTI 910 (Spring 2023) -
Directed Graduate Research
OPTI 792 (Fall 2022) -
Dissertation
OPTI 920 (Fall 2022) -
Nonlinear Photonics
OPTI 553 (Fall 2022) -
Thesis
OPTI 910 (Fall 2022)
2021-22 Courses
-
Dissertation
OPTI 920 (Spring 2022) -
Master's Report
OPTI 909 (Spring 2022) -
Photonics Innovation to Market
ECE 539A (Spring 2022) -
Photonics Innovation to Market
OPTI 439A (Spring 2022) -
Photonics Innovation to Market
OPTI 539A (Spring 2022) -
Thesis
OPTI 910 (Spring 2022) -
Dissertation
OPTI 920 (Fall 2021) -
Master's Report
OPTI 909 (Fall 2021) -
Nonlinear Photonics
OPTI 553 (Fall 2021) -
Thesis
OPTI 910 (Fall 2021)
2020-21 Courses
-
Directed Research
OPTI 492 (Summer I 2021) -
Research
OPTI 900 (Summer I 2021) -
Thesis
OPTI 910 (Summer I 2021) -
Directed Graduate Research
OPTI 792 (Spring 2021) -
Dissertation
OPTI 920 (Spring 2021) -
Photonics Innovation to Market
ECE 539A (Spring 2021) -
Photonics Innovation to Market
OPTI 439A (Spring 2021) -
Photonics Innovation to Market
OPTI 539A (Spring 2021) -
Thesis
OPTI 910 (Spring 2021) -
Directed Graduate Research
OPTI 792 (Fall 2020) -
Dissertation
OPTI 920 (Fall 2020) -
Nonlinear Photonics
OPTI 553 (Fall 2020) -
Thesis
OPTI 910 (Fall 2020)
2019-20 Courses
-
Research
OPTI 900 (Summer I 2020) -
Dissertation
OPTI 920 (Spring 2020) -
Photonics Innovation to Market
ECE 539A (Spring 2020) -
Photonics Innovation to Market
OPTI 439A (Spring 2020) -
Photonics Innovation to Market
OPTI 539A (Spring 2020) -
Thesis
OPTI 910 (Spring 2020) -
Dissertation
OPTI 920 (Fall 2019) -
Independent Study
OPTI 599 (Fall 2019) -
Nonlinear Photonics
OPTI 553 (Fall 2019)
2018-19 Courses
-
Directed Research
OPTI 492 (Summer I 2019) -
Dissertation
OPTI 920 (Spring 2019) -
Directed Graduate Research
OPTI 792 (Fall 2018) -
Dissertation
OPTI 920 (Fall 2018) -
Independent Study
OPTI 599 (Fall 2018)
2017-18 Courses
-
Directed Research
OPTI 492 (Summer I 2018) -
Dissertation
OPTI 920 (Summer I 2018) -
Dissertation
OPTI 920 (Spring 2018) -
Photonics Innovation to Market
ECE 539A (Spring 2018) -
Photonics Innovation to Market
OPTI 439A (Spring 2018) -
Photonics Innovation to Market
OPTI 539A (Spring 2018) -
Thesis
OPTI 910 (Spring 2018) -
Dissertation
OPTI 920 (Fall 2017) -
Honors Independent Study
OPTI 499H (Fall 2017) -
Master's Report
OPTI 909 (Fall 2017) -
Nonlinear Photonics
OPTI 553 (Fall 2017) -
Thesis
OPTI 910 (Fall 2017)
2016-17 Courses
-
Directed Graduate Research
OPTI 792 (Spring 2017) -
Dissertation
OPTI 920 (Spring 2017) -
Independent Study
OPTI 599 (Spring 2017) -
Photonics Innovation to Market
ECE 539A (Spring 2017) -
Photonics Innovation to Market
OPTI 439A (Spring 2017) -
Photonics Innovation to Market
OPTI 539A (Spring 2017) -
Thesis
OPTI 910 (Spring 2017) -
Dissertation
OPTI 920 (Fall 2016) -
Independent Study
OPTI 599 (Fall 2016) -
Master's Report
OPTI 909 (Fall 2016) -
Nonlinear Photonics
OPTI 553 (Fall 2016)
2015-16 Courses
-
Directed Research
OPTI 492 (Summer I 2016) -
Dissertation
OPTI 920 (Spring 2016) -
Independent Study
OPTI 599 (Spring 2016) -
Master's Report
OPTI 909 (Spring 2016) -
Photonics Innovation to Market
ECE 539A (Spring 2016) -
Photonics Innovation to Market
OPTI 439A (Spring 2016) -
Photonics Innovation to Market
OPTI 539A (Spring 2016) -
Thesis
OPTI 910 (Spring 2016)
Scholarly Contributions
Journals/Publications
- Norwood, R. A. (2022). 10-W picosecond Yb3+-doped all-fiber laser source at 976nm. IEEE Journal of Lightwave Technology, 40, 4415.
- Norwood, R. A. (2022). High Verdet constant materials for magneto-optical Faraday rotation: A review. Chemistry of Materials, 34, 2531.
- Norwood, R. A. (2022). High refractive index chalcogenide hybrid inorganic/organic polymers for integrated photonics. Advanced Optical Materials, 2022, 2200176.
- Norwood, R. A. (2022). Rapid photolithographic fabrication of high density optical interconnects using refractive index contrast polymers. Optical Materials Express, 12, 1932.
- Norwood, R. A. (2022). Single-frequency fiber laser at 880nm. Optics Express, 30, 32600.
- Norwood, R. A. (2022). SmartPrint single-mode flexible polymer optical interconnect for high density integrated photonics. IEEE Journal of Lightwave Technology, 40, 3839.
- Norwood, R. A. (2022). Sulfenyl chlorides: An alternative monomer feedstock from elemental sulfur for polymer synthesis. Journal of the American Chemical Society, 144, 23044.
- Norwood, R. A. (2021). Beyond 3 micron Dy3+/Er3+ co-doped ZBLAN fiber lasers pumped by 976nm laser diode. Applied Physics Letters, 118, 151101.
- Norwood, R. A. (2021). Design and characterization of a translucent solar module (TSM) for greenhouse structures. Journal of Engineering and Architecture, 8, 42.
- Norwood, R. A. (2021). Diode-pumped 1.15W linearly polarized single-frequency Yb3+ -doped phosphate fiber laser. Optics Express, 29, 30637.
- Norwood, R. A. (2021). Optical tuning of silicon nitride ring resonators using an external short visible wavelength laser source. OSA Continuum, 4, 1669.
- Norwood, R. A. (2021). Polymer-coated magnetic nanoparticles as ultra-high Verdet constant materials: Correlation of nanoparticle size with magnetic and magneto-optical properties. Chemistry of Materials, 33, 5010.
- Norwood, R. A. (2021). Relaxed tolerance low-loss adiabatic silicon nitride to polymer waveguide coupler for dense interconnects. IEEE Photonics Technology Letters, 33, 1227.
- Norwood, R. A. (2021). Single-freequency Nd3+-doped phophate fiber laser at 915nm. Journal of Lightwave Teechnology, 39, 1808.
- Norwood, R. A. (2021). Widely wavelength tunable Dy3+/Er3+ ZBLAN fiber lasers. Optics Express, 29, 38646.
- Norwood, R. A. (2020). 100th Anniversary of Macromolecular Science Viewpoint: High refractive index polymers with elemental sulfur for infrared thrmal imaging and optics. ACS Macroletters, 9, 245.
- Norwood, R. A. (2020). Cryogenic C-band wavelength division multiplexing system using an AIM Photonics process design kit. Optics Express, 28, 35651.
- Norwood, R. A. (2020). High-efficiency Nd3+-doped phosphate fiber laser at 880nm. IEEE Photonics Technology Letters, 32, 1179.
- Norwood, R. A. (2020). Magneto-optical properties of Dy3+ doped multicomponent glasses. Optics Express, 28, 11789.
- Norwood, R. A. (2020). Polymer and magnetic nanoparticle composites with tunable magneto-optical activity: role of nanoparticle dispersion for high Verdeet constant materials. Journal of Materials Chemistry C, 8, 5417.
- Norwood, R. A. (2020). Refractive index contrast polymers: Photoresponsive systeems with spatial modulation of refractive index for photonics. ACS Macroletters, 9, 416.
- Norwood, R. A. (2020). Thermal compensation of molded silicone optics. Applied Optics, 59, G99.
- Norwood, R. A. (2019). Infrared fingerprint engineering: A molecular design approach to long-wave infrared transparency with polymeric materials. Angewandte Chemie, 131, 1.
- Norwood, R. A. (2019). Investigation of ion-ion interaction effects on Yb3+-doped fiber amplifiers. Optics Express, 27, 28179.
- Norwood, R. A. (2019). Low-cost magneto-optic sensor based on tapered fiber and distributed sensing concept. IEEE Photonics Technology Letters, 31, 901.
- Norwood, R. A. (2019). Numerical investigationo of GHz repetition rate fundamentally mode-locked all-fiber lasers. Optics Express, 27, 14487.
- Norwood, R. A. (2019). SiO2 and TiO2 blends with tunable optical and electronic properties. MRS Advances, 4, 689.
- Norwood, R. A. (2019). Silicone optical elements for cost-effective freeform solar concentration. Optics Express, 27, A572.
- Norwood, R. A. (2018). Engineered nonlinear materials using gold nanoantenna array. Scientific Reports, 8, 780.
- Norwood, R. A. (2018). Nonlinear optical components for all-optical probabilistic graphical model. Nature Communicationsq, 9, 2128.
- Norwood, R. A. (2018). Nonlinear optical properties of chalcogenide hybrid inorganic/organic polymers (CHIPs) using the Z-scan technique. Optical Materials Express, 8, 2510.
- Norwood, R. A. (2018). One-dimensional photonic crystals using ultrahigh refractive index chalcogenide hybrid inorganic/organic polymers. ACS Macro Letters, 7, 875.
- Norwood, R. A. (2018). Optical and mechanical tolerances in hybrid concentrated thermal-PV solar trough. Optics Express, 26, A602.
- Norwood, R. A. (2018). Optical versus electronic implementation of probabilistic graphical infernce and experimental device demonstration using nonlinear photonics. IEEE Photonics Journal, 10, 7801412.
- Norwood, R. A. (2018). Power scalable 10W 976nm single-frequency linearly polarized laser source. Optics Letters, 43, 951.
- Norwood, R. A. (2017). Athermal silicon optical add-drop multiplexers based on thermo-optic coefficient tuning of sol-gel material. Optics Express, 25, 21471.
- Norwood, R. A. (2017). Chalcogenide hybrid inorganic/organic polymers: Ultrahigh refractive index polymers for infrared imaging. ACS Macroletters, 6, 500.
- Norwood, R. A. (2017). Efficient wafer-scale poling of electro-optic polymer thin films on soda-lime glass substrates: large second-order nonlinear coefficients and eceptional homogeneity of optical birefrinence. Optical Materials Express, 7, 1909.
- Norwood, R. A. (2017). Improving Faraday rotation performance with block copolymer and FePt nanoparticle magneto-optic composites. Optical Materials Express, 7, 2126.
- Norwood, R. A. (2017). Pulsed fluoride fiber lasers at 3 microns. Journal of the Optical Society of America B, 34, A15-A28.
- Norwood, R. A. (2017). Rapid visualization of grain boundaries in monolayer MoS2 by multiphoton microscopy. Nature Communications, 8, 15714.
- Norwood, R. A. (2017). Review of recent progress on single-frequency fiber lasers. Journal of the Optical Society of America B, 34, A49.
- Norwood, R. A. (2017). Ultrastrong nonlinear optical properties and trigonal warping in MoS2 layers. Nature Communications, 8, 893.
- Norwood, R. A. (2017). Yb3+ doped double-clad phosphate fiber for 976nm single-frequency laser amplifiers. Optical Materials Express, 7, 1310.
- Norwood, R. A. (2016). Designing spectrum-splitting dichroic filters to optimized current-matched photovoltaics. Applied Optics, 55, 1849.
- Norwood, R. A. (2016). Diffraction response of photorefractive polymers over nine orders of magnitude in pulse duration. Scientific Reports, 6, 29027.
- Norwood, R. A. (2016). Directed assembly of quantum dots using brush block copolymers for well-ordered nonlinear optical nanocomposites. Macromolecules, 49, 5068.
- Norwood, R. A. (2016). Dual-wavelength fiber laser operating above 2 microns based on cascaded single-mode-multimode-single-mode fiber structures. Optics Express, 24, 11282.
- Norwood, R. A. (2016). Graphene mode-locked fiber laser at 2.8 microns. IEEE Photonics Technology Letters, 28, 7.
- Norwood, R. A. (2016). High refractive index copolymers with imporved thermomechanical propeties via the inverse vulcanization of sulfur and 1,3,5-triisopropenylbenzene. ACS Macroletters, 5, 1152.
- Norwood, R. A. (2016). High-power, high-brightness terahertz source based on nonlinear optical crystal fiber. IEEE Journal of Selected Topics in Quantum Electronics, 22, 8500105.
- Norwood, R. A. (2016). High-repetition rate terahertz generation in QPM GaAs with a compact, efficient 2 micron KTP OPO. IEEE Photonics Technology Letters, 28, 1501.
- Norwood, R. A. (2016). Label-free multi-photon imaging of dysplasia in Barrett's esophagus. Biomedical Optics Express, 7, 148.
- Norwood, R. A. (2016). Mode-locked Ho3+-doped ZBLAN fiber laser at 1.2 micron. J. Lightwave Technology, 34, 4266.
- Norwood, R. A. (2016). Plasmonically induced potential in metal-semiconductor composites. Advanced Optical Materials, DOI: 10.1002/adom.2011600428.
- Norwood, R. A. (2016). Real-time dual-comb spectroscopy with a free-running bidirectionally mode-locked fiber laser. Applied Physics Letters, 108, 231104.
- Norwood, R. A. (2016). Second and third harmoni generation in few-layer gallium telluride characterized by multiphoton microscopy. Applied Physics Letters, 108, 073103.
- Norwood, R. A. (2016). Widely-tunable high-repetition-rate terahertz generation in GaSe with a compact dual-wavelength KTP OPO around 2 micron. Optics Express, 24, 23368.
- Norwood, R. A., Himmelhuber, R., Enami, Y., & Peyghambarian, N. (2015). Sol-gel material-enabled electro-optic polymer modulators. Sensors, 15, 18239.
- Norwood, R. A., Churin, D., Olson, J., Peyghambarian, N., & Kieu, K. (2015). High-power synchronously pumped femtosecond Raman fiber laser. Optics Letters, 40, 2529.
- Norwood, R. A., Cocilovo, B., Herrera, O. D., Mehravar, S., Fang, Y., Sandhage, K., & Kieu, K. (2015). Surface-enhanced two-photon excitation fluorescence of various fluorophores evaluated using a multiphioton microscope. Journal of Lightwave Technology. doi:10.1109/JLT.2015.2412126
- Norwood, R. A., Cocliovo, B., Hashimura, A., Tweet, D. J., & Voutsas, T. (2015). Highly transparent light-harvesting window film. Applied Optics, 54.
- Norwood, R. A., Gowda, R., Nguyen, N., Diels, J. C., Norwood, R. A., Peyghambarian, N., & Kieu, K. (2015). All-fiber bidirectional optical parametric oscillaator for precision sensing. Optics Letters, 40, 2033.
- Norwood, R. A., Griebel, J., Nguyen, N. A., Namnabat, S., Anderson, L. E., Glass, R. S., Mackay, M. E., Char, K., & Pyun, J. (2015). Dynamic covalent polymers via inverse vulcanization of elementl sulfur for healable infrared optical materials. ACS Macro Letters, 4, 862.
- Norwood, R. A., Jones, A., DeRose, C. T., Lentine, A., Starbuck, A., & Pomerene, A. T. (2015). Racetrack resonator as a loss measurement platform for photonic components. Optics Express, 23, 28883.
- Norwood, R. A., Karvonen, L., Saynatjoki, A., Meharavar, S., Rodriguez, R. D., Hartmann, S., Zahn, D. R., Honkanen, S., Peyghambarian, N., Kieu, K., Lipsanen, H., & Riikonen, J. (2015). Investigation of second- and third-harmonic generation in few layer gallium selenide by multiphoton microscopy. Scientific Reports, 5, 10334.
- Norwood, R. A., Khosroabadi, A. A., Gangopadhyay, P., Hernandez, S., Kim, K., & Peyghambarian, N. (2015). Nanoimprinted hybrid metal-semiconductor plasmonic multilayers with controlled surface nano architecture for applications in NIR detectors. Materials, 8, 5028.
- Norwood, R. A., Liu, P., Shi, W., Xu, D., Zhang, X., Yao, J., & Peyghambarian, N. (2015). High-power high-brightness terahertz source based on nonlinear optical crystal fiber. IEEE Journal of Selected Topics in Quantum Electronics, 22, 4900606.
- Norwood, R. A., Liu, S., Zhu, X., Balakrishnan, K., Zong, J., Wiersma, K., Chavez-Pirson, A., & Peyghambarian, N. (2015). Graphene Q-switched Ho3+-doped ZBLAN fiber laser at 1190nm. Optics Letters, 40, 147.
- Norwood, R. A., Lynn, B., Miles, A., Mehravar, S., Blanche, P., Kieu, K., & Peyghamabarian, N. (2015). Real-time imaging of chromophore alignment in photorefractive polymer devices through multiphoton microscopy. MRS Communications. doi:10.1557/mrc2015.31
- Norwood, R. A., Zhu, G., Geng, L., Zhu, X., Li, L., Chen, Q., Manzur, T., & Peyghambarian, N. (2015). Towards ten-watt 3-5 micron Raman lasers using tellurite fiber. Optics Express, 23, 7559.
- Shi, W., Norwood, R. A., Zhu, X., Fu, S., Sheng, Q., Yao, J., Shi, G., & Peyghambarian, N. (2015). Passive Q-switching of an all-fiber laser induced by the Kerr effect of multimode interference. Optics Express, 23, 17255.
- Khosroabadi, A. A., Matz, D. L., Gangopadhyay, P., Pemberton, J. E., & Norwood, R. A. (2014). Study of the C60/Ag Interface of a Large Area Nanoarchitectured Ag Substrate using Surface Enhanced Raman Scattering. Journal of Physical Chemistry C, 118, 18027-18034.
- Lau, P. C., Norwood, R. A., Mansuripur, M., & Peyghambarian, N. N. (2014). An effective nanosensor for organic molecules based on water-soluble mercaptopropionic acid-capped CdTe nanocrystals with potential application in high-throughput screening and high-resolution optical microscopy. Biomedical Optics Express, 5, 2420-2434.
- Norwood, R. A. (2014). A novel approach for microsensing: Detecting and identifying eigenmodes of sensing objects. Journal of Analytical and Bioanalytical Techniques.
- Norwood, R. A. (2014). An effective nanosensor for organic molecules based on water-soluble mercaptoproprionic acid-capped CdTe nanocrystals with potential application in high-throughput screening and high-resolution optical microscopy. Biomedical Optics Express, 5, 2420.
- Norwood, R. A. (2014). Characterization of coplanar poled electro-optic polymer films for Si-photonc devices with multiphoton microscopy. Applied Physics Letters, 104, 161109.
- Norwood, R. A. (2014). Enhanced magnetisim in highly ordered magnetite nanoparticle-filled nanohole arrays. Small, 10, 2840-2848.
- Norwood, R. A. (2014). Faraday rotation of cobalt ferrite nanoparticel polymer composite films at cryogenic temperatures. Applied Optics, 53, 2087.
- Norwood, R. A. (2014). Fiber lasers and their applications. Applied Optics, 53, 6554.
- Norwood, R. A. (2014). Microwave properties of MAPTMS sol-gel films for high-speed electro-optic devices. IEEE Trans. Microwave Theory and Techniques, 62, 1599.
- Norwood, R. A. (2014). Multiphoton microscopy as a detection tool for photobleaching in EO materials. Optics Express, 22, 30955.
- Norwood, R. A. (2014). New infrared transmitting material via inverse vulcanization of elemental sulfur to prepare high refractive index polymer. Advanced Materials, 26, 3014.
- Norwood, R. A. (2014). Observation of two-photon fluorescence for Rhodamine 6G in microbubble resonators. Optics Letters, 39, 3098.
- Norwood, R. A. (2014). Raman-induced frequency shift in carbon disulfide filled integrated liquid-core optical fiber. Optics Communications, 318, 83.
- Norwood, R. A. (2014). Silica/electro-optic polymer optical modulator with integrated antenna for microwave receiving. Journal of Lightwave Technology, 32, 3861.
- Norwood, R. A. (2014). Structure-based optical filtering by the silica microshell of the centric marine diatom Cosconodiscus wailessi. Optics Express, 22, 15992.
- Norwood, R. A. (2014). Study of the C60/Ag interface of a large area nanoarchitectured Ag substrate using surface-enhaced Raman scattering. J. Phys. Chem. C, 118, 18027.
- Norwood, R. A. (2014). Third-order nonlinear optical characterization of organic chromopohres using liquid-core optical fibers. Journal of the Optical Society of America B, 31, 2455.
- Norwood, R. A. (2014). Total internal reflection magneto-optical detection of dysprosium (III) ions adsorbed at liquid-liquid interface. Chemistry Letters, 43, 1651.
- Norwood, R. A. (2014). Watt-level short-length Ho3+-doped ZBLAN fiber laser at 1.2 micron. Optics Letters, 39, 1533.
- Jones, A. M., DeRose, C. T., Lentine, A. L., Trotter, D. C., Starbuck, A. L., & Norwood, R. A. (2013). Ultra-low crosstalk, CMOS compatible waveguide crossings for densely integrated photonic interconnection networks. Optics Express, 21(10), 12002-12013.More infoPMID: 23736422;Abstract: We explore the design space for optimizing CMOS compatible waveguide crossings on a silicon photonics platform. This paper presents simulated and experimental excess loss and crosstalk suppression data for vertically integrated silicon nitride over silicon-on-insulator waveguide crossings. Experimental results show crosstalk suppression exceeding -49/-44 dB with simulation results as low as -65/-60 dB for the TE/TM mode in a waveguide crossing with a 410 nm vertical gap. © 2013 Optical Society of America.
- Jones, A. M., Derose, C. T., Lentine, A. L., Trotter, D. C., Starbuck, A., & Norwood, R. A. (2013). Layer separation optimization in CMOS compatible multilayer optical networks. 2013 Optical Interconnects Conference, OI 2013, 62-63.More infoAbstract: We explore the design space surrounding a CMOS compatible silicon nitride over silicon-on-insulator 3D optical layer for photonic interconnection networks and compare the results with single layer approaches. © 2013 IEEE.
- Khosroabadi, A. A., & Norwood, R. A. (2013). Spectroscopic ellipsometry study of novel nanostructured transparent conducting oxide structures. Proceedings of SPIE - The International Society for Optical Engineering, 8632.More infoAbstract: Spectroscopic ellipsometry has been used to find the optical constants, including refractive index, extinction coefficient, thickness and volume fraction of nanostructured transparent conducting oxides including indium tin oxide (ITO) and indium zinc oxide (IZO). We observed sharp features in the ellipsometry data, with the spectral peaks and positions depending on the nanostructure dimensions and material. A superposition of Lorentzian oscillators and the effective medium approximation has been applied to determine the volume ratio of voids and nanopillars, thereby providing the effective optical constants. © 2013 SPIE.
- Nguyen, D. T., & Norwood, R. A. (2013). Label-free, single-object sensing with a microring resonator: FDTD simulation. Optics Express, 21(1), 49-59.More infoPMID: 23388895;Abstract: Label-free, single-object sensing with a microring resonator is investigated numerically using the finite difference time-domain (FDTD) method. A pulse with ultra-wide bandwidth that spans over several resonant modes of the ring and of the sensing object is used for simulation, enabling a single-shot simulation of the microring sensing. The FDTD simulation not only can describe the circulation of the light in a whispering-gallery-mode (WGM) microring and multiple interactions between the light and the sensing object, but also other important factors of the sensing system, such as scattering and radiation losses. The FDTD results show that the simulation can yield a resonant shift of the WGM cavity modes. Furthermore, it can also extract eigenmodes of the sensing object, and therefore information from deep inside the object. The simulation method is not only suitable for a single object (single molecule, nano-, micro-scale particle) but can be extended to the problem of multiple objects as well. © 2013 Optical Society of America.
- Norwood, R. A. (2013). Biological and biologically inspired photonic materials and devices. Proceedings of SPIE - The International Society for Optical Engineering, 8817.More infoAbstract: We discuss the increasing effort to adopt biological and biologically inspired concepts to solve problems in photonic materials and devices. This effort ranges from exploiting fundamental material properties, as in fluorescent dyes and DNA-derived polymers, to studying structures that interact strongly with photons, exemplified by butterfly wings. An emerging area of interest is the combination of biological or biologically derived materials with organic or inorganic synthetic materials to achieve material systems with unprecedented performance. We discuss several examples from our recent work including erbium-doped solgel/ DNA-CTMA, diatom photonics, and microring resonator based sensing of biological objects. © 2013 SPIE.
- Norwood, R. A. (2013). Hybrid electro-optic polymer modulators for RF photonics. 2013 IEEE Avionics, Fiber-Optics and Photonics Technology Conference, AVFOP 2013, 45-46.
- Norwood, R. A. (2013). Organic photonics: Ready for prime time. Optics and Photonics News, 24(11), 40-47.
- Norwood, R., Cocilovo, B., Amooali, A., Lopez-Santiago, A., Favela, J., Islam, S., Duong, B., Gangopadhyay, P., Fallahi, M., Pemberton, J. E., Thomas, J., & Norwood, R. A. (2013). Effect of modular diffraction gratings on absorption in P3HT:PCBM layers. Applied optics, 52(5).More infoVarious gratings with 700 nm feature spacings are patterned on the reverse side of organic solar cell active layers to increase the path length and constrain light to the cell through total internal reflection. The absorption enhancement is studied for 15, 40, and 120 nm active layers. We were able to confine 9% of the incident light over the wavelength range of 400-650 nm, with thinner gratings having a greater enhancement potential. The measurement setup utilizing an integrating sphere to fully characterize scattered or diffracted light is also fully described.
- Norwood, R., Nguyen, D. T., & Norwood, R. A. (2013). Label-free, single-object sensing with a microring resonator: FDTD simulation. Optics express, 21(1).More infoLabel-free, single-object sensing with a microring resonator is investigated numerically using the finite difference time-domain (FDTD) method. A pulse with ultra-wide bandwidth that spans over several resonant modes of the ring and of the sensing object is used for simulation, enabling a single-shot simulation of the microring sensing. The FDTD simulation not only can describe the circulation of the light in a whispering-gallery-mode (WGM) microring and multiple interactions between the light and the sensing object, but also other important factors of the sensing system, such as scattering and radiation losses. The FDTD results show that the simulation can yield a resonant shift of the WGM cavity modes. Furthermore, it can also extract eigenmodes of the sensing object, and therefore information from deep inside the object. The simulation method is not only suitable for a single object (single molecule, nano-, micro-scale particle) but can be extended to the problem of multiple objects as well.
- Sheng, C. -., Wang, R. Z., Li, H., Chen, Q., & Norwood, R. A. (2013). Nonlinear optical transmission of lead phthalocyanines in polymeric matrix. Proceedings of SPIE - The International Society for Optical Engineering, 8924.More infoAbstract: We have made lead (II) tetrakis (4-cumylphenoxy) phthalocyanine (PbTCPc) films with various concentrations in plasticized poly (methyl methacrylate) (PMMA) and poly (acrylic tetraphenyl diaminobiphenylamine) (PATPD) matrices, and investigated nonlinear transmission properties with a Nd:YAG laser (532 nm, 5ns). Our results demonstrate a solid state PbTCPc nonlinear absorber, whose performance is comparable to that of low concentration solutions of the dye, that can be fabricated by mixing the dye in a plasticized polymer matrix. © 2013 SPIE.
- Wang, Z., Ingram, P., Greenlee, C. L., Olafsson, R., Norwood, R. A., & Witte, R. S. (2013). Design considerations and performance of MEMS acoustoelectric ultrasound detectors. IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 60(9), 1906-1916.More infoAbstract: Most single-element hydrophones depend on a piezoelectric material that converts pressure changes to electricity. These devices, however, can be expensive, susceptible to damage at high pressure, and/or have limited bandwidth and sensitivity. We have previously described the acoustoelectric (AE) hydrophone as an inexpensive alternative for mapping an ultrasound beam and monitoring acoustic exposure. The device exploits the AE effect, an interaction between electrical current flowing through a material and a propagating pressure wave. Previous designs required imprecise fabrication methods using common laboratory supplies, making it difficult to control basic features such as shape and size. This study describes a different approach based on microelectromechanical systems (MEMS) processing that allows for much finer control of several design features. In an effort to improve the performance of the AE hydrophone, we combine simulations with bench-top testing to evaluate key design features, such as thickness, shape, and conductivity of the active and passive elements. The devices were evaluated in terms of sensitivity, frequency response, and accuracy for reproducing the beam pattern. Our simulations and experimental results both indicated that designs using a combination of indium tin oxide (ITO) for the active element and gold for the passive electrodes (conductivity ratio = ~20) produced the best result for mapping the beam of a 2.25-MHz ultrasound transducer. Also, the AE hydrophone with a rectangular dumbbell configuration achieved a better beam pattern than other shape configurations. Lateral and axial resolutions were consistent with images generated from a commercial capsule hydrophone. Sensitivity of the bestperforming device was 1.52 nV/Pa at 500 kPa using a bias voltage of 20 V. We expect a thicker AE hydrophone closer to half the acoustic wavelength to produce even better sensitivity, while maintaining high spectral bandwidth for characterizing medical ultrasound transducers. AE ultrasound detectors may also be useful for monitoring acoustic exposure during therapy or as receivers for photoacoustic imaging. © 1986-2012 IEEE.
- Zhang, C., Zhang, L., Benight, S. J., Olbricht, B. C., Johnson, L. E., Robinson, B. H., Norwood, R. A., & Dalton, L. R. (2013). Shape engineering to promote head-tail interactions of electro-optic chromophores. Proceedings of SPIE - The International Society for Optical Engineering, 8827.More infoAbstract: Alignment of dipolar chromophores lies at the heart of organic electro-optic materials research. Among all the factors (e.g., external electric field, temperature, conductivity, etc.) affecting alignment efficiency or order parameter, interchromophore electrostatic interaction has been the focus of attention in the last decade. The strength of dipole interaction is highly dependent not only on dipole moment but also on chromophore shape and chromophore number density. Antiparallel interaction is dominant in the solid state of conventional EO chromophores (long and flat) and prevents electro-optic coefficient (r33) from scaling with chromophore concentration. Despite the great amount of research along various approaches to enhancing alignment, order parameters of organic EO materials are still low (0.13- 0.2 v.s. 1 for a perfect alignment). Antiparallel interaction can be selectively attenuated by attaching bulky groups to the middle part of chromophore. However, it is synthetically challenging to provide sufficient steric protection without causing severe reduction of chromophore concentration. In this paper, we will present the first realization of atomeconomic steric protection of chromophore against H-aggregation in all directions and show evidences for the dominance of head-tail interaction over antiparallel interaction of a highly dipolar chromophore. With the novel shape, the EO coefficients of guest-host films of the chromophore do not show attenuation with increasing concentration up to 100 wt%. The dominance of head-tail interaction also enabled fabrication of optical quality thick films from the neat chromophore and allows poling induced alignment to retain at temperatures above the poling temperature - a phenomenon never observed for other chromophores. © 2013 SPIE.
- Boulanger, B., Cundiff, S. T., Gauthier, D. J., Karlsson, M., Lu, Y., Norwood, R. A., Skryabin, D., & Taira, T. (2011). Focus issue introduction: Nonlinear optics. Optical Materials Express, 1(7), 1393-1398.More infoAbstract: It is now fifty years since the original observation of second harmonic generation ushered in the field of nonlinear optics, close on the heels of the invention of the laser. This feature issue celebrates this anniversary with papers that span the range from new nonlinear optical materials, through the increasingly novel methods that have been developed for phase matching, to emerging areas such as nonlinear metamaterials and plasmonic enhancement of optical properties. It is clear that the next fifty years of nonlinear optics will witness a proliferation of new applications with increasing technological impact. © 2011 Optical Society of America.
- Boulanger, B., Cundiff, S. T., Gauthier, D. J., Karlsson, M., Lu, Y., Norwood, R. A., Skryabin, D., & Taira, T. (2011). Focus issue introduction: Nonlinear optics. Optics Express, 19(23), 23561-23566.More infoPMID: 22109235;Abstract: It is now fifty years since the original observation of second harmonic generation ushered in the field of nonlinear optics, close on the heels of the invention of the laser. This feature issue celebrates this anniversary with papers that span the range from new nonlinear optical materials, through the increasingly novel methods that have been developed for phase matching, to emerging areas such as nonlinear metamaterials and plasmonic enhancement of optical properties. It is clear that the next fifty years of nonlinear optics will witness a proliferation of new applications with increasing technological impact. © 2011 Optical Society of America.
- Ingram, P., Greenlee, C. L., Wang, Z., Olafsson, R., Norwood, R. A., & Witte, R. S. (2010). Fabrication and characterization of an indium tin oxide acoustoelectric hydrophone. Progress in Biomedical Optics and Imaging - Proceedings of SPIE, 7629.More infoAbstract: Clinical ultrasound (US) imaging and therapy require a precise knowledge of the intensity distribution of the acoustic field. Although piezoelectric hydrophones are most common, these devices are limited in terms of, for example, type of materials, cost, and performance at high frequency and pressure. As an alternative to conventional acoustic detectors, we describe acoustoelectric hydrophones, developed using photolithographic fabrication techniques, where the induced voltage (phase and amplitude) is proportional to both the US pressure and bias current injected through the device. In this study a number of different hydrophone designs were created using indium tin oxide (ITO). A constriction of the current path within the hydrophone created a localized "sensitivity zone" of high current density. The width of this zone ranged from 30 to 1000 μm, with a thickness of 100 nm. A raster scan of the US transducer produced a map of the acoustic field. Hydrophones were evaluated by mapping the pressure field of a 2.25 MHz single element transducer, and their performance was compared to a commercial capsule hydrophone. Focal spot sizes at -6 dB were as low as 1.75 mm, comparing well with the commercial hydrophone measurement of 1.80 mm. Maximum sensitivity was 2 nV/Pa and up to the 2nd harmonic was detected. We expect improved performance with future devices as we optimize the design. Acoustoelectric hydrophones are potentially cheaper and more robust than the piezoelectric models currently in clinical use, potentially providing more choice of materials and designs for monitoring therapy or producing arrays for imaging. © 2010 Copyright SPIE - The International Society for Optical Engineering.
- Khanna, A., Säynätjoki, A., Tervonen, A., Norwood, R. A., & Honkanen, S. (2010). Polarization properties of two-dimensional slot waveguides. Applied Optics, 49(28), 5321-5332.More infoPMID: 20885468;Abstract: We propose and study slot waveguide geometries where both quasi-TE and quasi-TM modes may propagate highly confined within the same low-index slot region. Conventional horizontal and vertical slot waveguides can only provide high slot confinement for either the quasi-TM or quasi-TE modes, respectively. Different two-dimensional slot waveguide structures are analyzed in terms of their mode characteristics, such as the effective index, the confinement factor, and the overlap of quasi-TE and -TM modes within the slot. Attention is also paid to practical manufacturability. Various waveguide structures can be tailored to have zero birefringence or equal confinement at both polarizations. Values for the confinement factors and the overlap of the two polarizations, in the slot region, can reach 0.4 to 0.5. © 2010 Optical Society of America.
- Wang, Z., Ingram, P., Olafsson, R., Greenlee, C. L., Norwood, R. A., & Witte, R. S. (2010). Simulation-based optimization of the acoustoelectric hydrophone for mapping an ultrasound beam. Progress in Biomedical Optics and Imaging - Proceedings of SPIE, 7629.More infoAbstract: Most single element hydrophones depend on a piezoelectric material that converts pressure changes to electricity. These devices, however, can be expensive, susceptible to damage at high pressure, and/or have limited bandwidth and sensitivity. The acousto-electric (AE) hydrophone is based on the AE effect, an interaction between electrical current and acoustic pressure generated when acoustic waves travel through a conducting material. As we have demonstrated previously, an AE hydrophone requires only a conductive material and can be constructed out of common laboratory supplies to generate images of an ultrasound beam pattern consistent with more expensive hydrophones. The sensitivity is controlled by the injected bias current, hydrophone shape, thickness and width. In this report we describe simulations aimed at optimizing the design of the AE hydrophone with experimental validation using new devices composed of a resistive element of indium tin oxide (ITO). Several shapes (e.g., bowtie and dumbbell) and resistivities were considered. The AE hydrophone with a dumbbell configuration achieved the best beam pattern of a 2.25MHz ultrasound transducer with lateral and axial resolutions consistent with images generated from a commercial hydrophone (Onda Inc.). The sensitivity of this device was ∼2 nV/Pa. Our simulations and experimental results both indicate that designs using a combination of ITO and gold (ratio of resistivities = ∼18) produce the best results. We hope that design optimization will lead to new devices for monitoring ultrasonic fields for biomedical imaging and therapy, including lithotripsy and focused ultrasound surgery. © 2010 Copyright SPIE - The International Society for Optical Engineering.
- Chen, X., Thomas, J., Gangopadhyay, P., Norwood, R. A., Peyghambarian, N., & McGrath, D. V. (2009). Modification of symmetrically substituted phthalocyanines using click chemistry: Phthalocyanine nanostructures by nanoimprint lithography. Journal of the American Chemical Society, 131(38), 13840-13843. doi:http://doi.org/10.1021/ja905683gMore infoPMID: 19772367;Abstract: Phthalocyanines (Pcs) are commonly applied to advanced technologies such as optical limiting, photodynamic therapy (PDT), organic field-effect transistors (OFETs), and organic photovoltaic (OPV) devices, where they are used as the p-type layer. An approach to Pc structural diversity and the incorporation of a functional group that allows fabrication of solvent resistant Pc nanostructures formed by using a newly developed nanoimprint by melt processing (NIMP) technique, a variant of standard nanoimprint lithography (NIL), is reported. Copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC), a click chemistry reaction, serves as an approach to structural diversity in Pc macrocycles. We have prepared octaalkynyl Pc 1b and have modified this Pc using the CuAAC reaction to yield four Pc derivatives 5a-5d with different peripheral substituents on the macrocycle. One of these derivatives, 5c, has photo-cross-linkable cinnamate residues, and we have demonstrated the fabrication of robust cross-linked photopatterned and imprinted nanostructures from this material. © 2009 American Chemical Society.
- Hatton, B., Mishchenko, L., Norwood, R., Davis, S., Sandhage, K., & Aizenberg, J. (2009). An evaporative co-assembly method for highly-ordered inverse opal films. Proceedings of SPIE - The International Society for Optical Engineering, 7205.More infoAbstract: Colloidal self-assembly holds promise for photonic applications as a solution-based, low-cost alternative to top-down photolithography, if significant control of uniformity and defects can be achieved. Herein we demonstrate a new evaporative co-assembly method for highly-uniform inverse opal thin films that involves the self-assembly of polymer colloids in a solution containing a silicate precursor. Nanoporous inverse opal films can be made crack-free and with highly uniform orientation at the cm scale. The silicate between the colloids appears to increase the strength against cracking. This control of defects makes this method well-suited for the low cost fabrication of such films as sensors and photonic devices. © 2009 SPIE.
- Norwood, R. A. (2008). Electro-optic polymer modulators for telecommunications applications. OFC/NFOEC 2008 - 2008 Conference on Optical Fiber Communication/National Fiber Optic Engineers Conference.More infoAbstract: Recent progress in electro-optie (EO) polymer materials and hybrid device designs have led to the demonstration of electro-optic modulators with unprecedented bandwidth (>100GHz) and drive voltage (̃ 0.5V). We will discuss our development of hybrid EO polymer/sol-gel waveguide modulators that achieve sub-volt drive voltages and superior photostability, while using a low-cost wet etch fabrication process. We also present a figure of merit that assists in the comparison of different EO po/ymer/cladding systems. © 2007 Optical Society of America.
- Novotny, C. J., DeRose, C. T., Norwood, R. A., & Yu, P. K. (2008). Linear electrooptic coefficient of InP nanowires. Nano Letters, 8(4), 1020-1025.More infoPMID: 18311932;Abstract: A novel fabrication procedure is developed that allows for the direct measurement of the linear electrooptic coefficient of semiconducting nanowires to determine their viability for use in electrooptic devices. Vertically aligned InP nanowires are transferred from their growth substrate to a glass substrate using a host polymer, while still retaining the alignment of the nanowires. The linear electrooptic coefficient of the InP nanowires exhibited a 1-2 orders of magnitude enhancement over bulk InP and ranged from 31 to 147 pm/V. The figure of merit, n 3r, exhibited a factor of 20 enhancement over lithium niobate and ranged from 1010 to 4817 pm/V. © 2008 American Chemical Society.
- Norwood, R. A. (2007). Hybrid electro-optic polymer devices: Beating the drive voltage/insertion loss trade-off. LEOS Summer Topical Meeting, 198-199.More infoAbstract: We have developed a solution to the voltage/insertion loss tradeoff in electro-optic polymer modulators by adopting hybrid geometry. We will discuss recent results in these devices, notably the achievement of r33 = 170pm/V in a device. © 2007 IEEE.
- Norwood, R., Eich, M., & Nunzi, J. (2006). Proceeding of SPIE - The International Society for Optical Engineering: Introduction. Proceedings of SPIE - The International Society for Optical Engineering, 6331, ix.
- Norwood, R. A. (2004). Optical polymers: Critical requirements for optical access applications. Proceedings of SPIE - The International Society for Optical Engineering, 5517, 124-133.More infoAbstract: Optical access networks currently present some of the most exciting potential applications for integrated photonic devices, in particular those based on polymers. With fiber-to-the-premise (FTTP) initiatives at leading metropolitan area carriers well underway, there is keen interest in the development of low cost, highly integrated components that can withstand an outside plant environment (-40°C to 85°C). As opposed to polymers that have been developed for complex highly integrated optical circuits, polymers suitable for optical access deployment will need to address numerous optoelectronic packaging integration issues, notably alignment with active devices, compatibility with high-volume electronics manufacturing and management of thermal loads. We discuss the critical requirements that optical polymers must meet to address optical access applications, and identify those that can be met by existing technologies and those presenting gaps to be bridged for successful development of optical access components.
- Norwood, R. A. (2004). Proceedings of SPIE - The International Society for Optical Engineering: Introduction. Proceedings of SPIE - The International Society for Optical Engineering, 5517, ix.
- Norwood, R. A. (2001). Erratum: (Design, Manufacturiing, and Testing of Planar Optical Waveguide Devices (1 August 2001)). Proceedings of SPIE - The International Society for Optical Engineering, 4439, 115-.
- Norwood, R. A. (2001). Hybrid polymer devices for improved thermal control and performance. Proceedings of SPIE - The International Society for Optical Engineering, 4289, 130-140.More infoAbstract: Single-mode waveguides based on planar silica have found increasing application in passive optical components such as arrayed waveguide gratings (AWG), couplers, and splitters. Key aspects of these devices are their low insertion losses and relative insensitivity to temperature. Planar polymer waveguides present a complementary technology that is finding deployment in thermally activated components such as thermo-optic switches, variable attenuators and tunable filters. This results from the large thermo-optic effects and low thermal conductivities in polymers that lead to low power, compact and rapid thermal activation. There are a number of advantages to moving toward a hybridization of the two technologies. In some cases, the opposite signs of the thermo-optic effect in silica and polymers can be used to achieve virtually a thermal performance for highly phase sensitive devices such as AWGs. Polymer overcladdings of appropriate refractive index and optical loss can also be used to reduce stresses in thick silica waveguides. A further advantage of combining these two materials technologies is to realize waveguide chips of higher functionality and performance that combine both passive and thermally activated functions. In this way the low propagation loss of silica waveguides can be used for transmission operations, while selectively placed polymer waveguide can be used for switching and attenuation, for example. We present several examples, consider fundamental materials issues, and identify potential routes to further exploitation of hybrid polymer/silica devices in next generation optical modules.
- Norwood, R. A. (2001). Proceedings of SPIE - The International Society for Optical Engineering: Introduction. Proceedings of SPIE - The International Society for Optical Engineering, 4439, vii.
- Norwood, R. A., Gao, R., Sharma, J., & Teng, C. C. (2001). Sources of loss in single-mode polymer optical waveguides. Proceedings of SPIE - The International Society for Optical Engineering, 4439, 19-28.More infoAbstract: Single-mode optical waveguides based on planar silica have found increasing application in passive optical components such as arrayed waveguide gratings (AWG), couplers, and splitters. Key aspects of these devices are their low insertion losses and relative insensitivity to temperature. Planar polymer waveguides present a complementary technology that is finding deployment in thermally activated components such as thermo-optic switches, variable attenuators and tunable filters. This results from the large thermo-optic effects and low thermal conductivities in polymers that lead to low power, compact and rapid thermal activation. However, the widespread deployment of planar polymer waveguides has been slowed by inability of single-mode polymer waveguides to achieve the low waveguide losses that have been attained in planar silica. In this paper we look at the sources of loss in polymer optical waveguides, assess approaches to reducing losses, and discuss several important loss measurement techniques valuable for evaluation of new polymer materials.
- Eldada, L., Norwood, R., Blomquist, R., Shacklette, L. W., & McFarland, M. J. (2000). Thermo-optically active polymeric photonic components. Conference on Optical Fiber Communication, Technical Digest Series, 2, 124-126.More infoAbstract: Devices that include a variety of filtering, routing, switching, and attenuating elements are presented. These devices are Bragg-grating-based wavelength filters that are thermally tunable over the Erbium C-band window, tunable arrayed waveguide gratings (AWGs), digital optical switches (DOSs) that exhibit low power consumption and high isolation, and fused variable optical attenuators (VOAs) with high thermal sensitivity and wide dynamic ranges.
- Gao, R., Norwood, R. A., Teng, C. C., & Garito, A. F. (2000). Rare earth-doped polymer optical waveguide amplifiers. Proceedings of SPIE - The International Society for Optical Engineering, 3939, 12-26.More infoAbstract: The optical properties and characteristics of rare earth-doped polymers have been studied to evaluate their viability for use in optical amplifiers. Rare earth ions are encapsulated in organic, covalently bonded chromophores. The optical properties of various rare earth chromophores doped into polymers are measured and calculated and are then used in numerical simulations of amplifiers and lasers. The results provide an estimate of their potential device performance and establish the fundamental bases for applications in photonics. Owing to their distinct advantages, such as chromophore energy transfer effects, high rare earth ion concentrations, shielding of the ion from high energy vibrations of the host, enhanced optical transition moments, and controllable decay rates and branching ratios, rare earth-doped polymers are found to be promising candidates for various device applications. Numerical simulations for samarium and europium doped polymers indicate that gains about 10 dB and greater are achievable in relatively short polymer optical fiber and waveguide amplifiers. Studies of the dependence of metastable state lifetime of rare earth doped polymer systems on doping concentration reveal that rare earth chromophore dissociation occurs at low concentrations. These results are used to optimize the parameters of our rare earth doped polymer optical waveguide amplifiers.
- Blomquist, R., Eldada, L., McFarland, M., Norwood, R., Poga, C., & Shacklette, L. (1999). Fluorinated acrylates in making low-loss, low-birefringence, and single-mode optical waveguides with exceptional thermo-optic properties. Proceedings of SPIE - The International Society for Optical Engineering, 3799, 266-279.More infoAbstract: There is growing interest in the use of planar waveguide devices in telecommunications. Polymeric planar waveguide devices are of special interest in thermo-optic devices because of their high values for dn/dT. This paper details the possible choices in different photolithographic systems that could be used in making such devices. This paper explains the benefits of using fluorinated acrylates in achieving low-loss waveguides with low birefringence. It also explains the unique benefits of fluorinated acrylates in making Bragg gratings.
- Eldada, L., Blomquist, R., Maxfield, M., Pant, D., Boudoughian, G., Poga, C., & Norwood, R. A. (1999). Thermally tunable polymer Bragg grating OADM's. Conference on Optical Fiber Communication, Technical Digest Series, p 3.More infoAbstract: Bragg-grating-based optical add/drop multiplexers (OADM) are designed and produced, that are compatible with the advanced planar polymer waveguide technology. Gratings with 99.997% reflection efficiencies were produced, apodization was use to eliminate sidelobes, and symmetry was ensured to avoid coupling to cladding modes. Thermal solid-state tuning over a range of 20 nm was achieved with a single device.
- Eldada, L., Blomquist, R., Maxfield, M., Pant, D., Boudoughian, G., Poga, C., & Norwood, R. A. (1999). Thermooptic planar polymer Bragg grating OADM's with broad tuning range. IEEE Photonics Technology Letters, 11(4), 448-450.More infoAbstract: Tunable optical add/drop multiplexers (OADM's) were achieved by combining thermally tunable planar polymer Bragg gratings with optical circulators. The gratings exhibit better than 45-dB reflection with no detectable out-of-band reflection. Apodization was utilized to achieve strong sidelobe suppression, and symmetric gratings with uniform strength across the core and cladding layers were used to minimize coupling to cladding modes. These OADM's have a high-bandwidth utilization (BWU) factor of 0.92, with a minimum channel spacing of 75 GHz. They are tunable at a rate of -0.256 nm/°C. Tuning over a 20-nm range was demonstrated with a single device.
- Poga, C., Blomquist, R., Eldada, L., & Norwood, R. A. (1999). Polymer Bragg gratings for wavelength division multiplexers. Proceedings of SPIE - The International Society for Optical Engineering, 3633, 81-91.More infoAbstract: An advanced versatile, low-cost polymeric waveguide technology with Bragg gratings has been developed for filter applications in optical communications. Bragg gratings are photochemically formed in single mode polymeric waveguides using holographic techniques. The resulting gratings exhibit excellent filter characteristics; 99.997% reflectivity in a 2 cm grating, which corresponds to refractive index modulation of the order of 10-3, 0.2 nm width in the reflection peak at the 3dB point in reflectivity, and no sidelobes in the reflection spectrum. The mechanism of the grating formation is discussed; its understanding enables us to enhance the filter characteristics of the gratings. The impact of temperature and humidity on the filter performance is also presented. The shift of the reflection maximum is 0.23 nm/°C. The Bragg shift for a 90% change in relative humidity is 0.2 nm.
- Viens, J. -., Callender, C. L., Noad, J. P., Eldada, L., & Norwood, R. A. (1999). Polymer-based waveguide devices for WDM applications. Proceedings of SPIE - The International Society for Optical Engineering, 3799, 202-213.More infoAbstract: This paper summarizes the work currently in progress at CRC Canada on wavelength division multiplexing (WDM) components based on polymer waveguide devices for operation at 1550 nm. Planar arrayed waveguide gratings (AWGs) of various bandwidths were designed, fabricated and tested using acrylate polymer materials developed by AlliedSignal Inc.. Eight-channel polymer demultiplexers fabricated by standard lithography show on-chip losses of 8 dB and a crosstalk of -25 dB between channels spaced 1.6 nm apart. Owing to the thermo-optic properties of these polymers, the spectral response of the devices can be tuned by more than 7 nm without changes in optical crosstalk or on-chip loss. Very compact AWGs made with AlliedSignal polymers are being designed and tested to address the need for cost effective, high bandwidth optical components in the telecom and datacom industries.
- Eldada, L., Yin, S., Poga, C., Glass, C., Blomquist, R., & Norwood, R. A. (1998). Integrated multichannel OADM's using polymer bragg grating MZI's. IEEE Photonics Technology Letters, 10(10), 1416-1418.More infoAbstract: We report the first fabrication of Bragg-grating-based multichannel optical add/drop multiplexers (OADM's) in planar polymers. The filters were designed by cascading multiple stages of single-channel multi-/demultiplexers. Each stage consists of a Mach-Zehnder interferometer (MZI) with a Bragg grating across its arms. The 3-dB couplers in each MZI are multimode interference (MMI) couplers. We fabricated the first tapered MMI couplers, which provide compactness. The gratings were printed photochemically, achieving index differences as high as 10 -3 and reflectivities as large as 33 dB. The 3-dB bandwidth is about 0.2 nm. Apodization was used to reduce sidelobes in the reflection spectrum. Four-channel OADM's were produced and exhibited the proper 400-GHz channel separation and ITU grid wavelength alignment, as well as excellent channel isolation and uniform channel response.
- Norwood, R. A., Blomquist, R., Eldada, L., Glass, C., Poga, C., Shacklette, L. W., Xu, B., Yin, S., & Yardley, J. T. (1998). Polymer integrated optical devices for telecommunications applications. Proceedings of SPIE - The International Society for Optical Engineering, 3281, 2-13.More infoAbstract: The success of optical fiber technology continues to enable great advances in telecommunications. Among the more recent commercial developments have included the erbium doped fiber amplifier, 10 GB/sec time division multiplexing, and dense wavelength division multiplexing (DWDM). In the near future two trends will dominate the continued growth of this technology (1) increased optical device functionality and (2) migration of increased bandwidth down to local loop and access levels of the network. Examples of increased functionality will include splitters and DWDM's with increased port counts, wavelength conversion, and matrix optical switching. Migration of bandwidth will require greater volumes of fundamental optical components such as power splitters and WDM's. We will discuss our polymeric optical device technology in light of both current and future telecom needs. We have developed a series of cross-linked polymers with intrinsic losses in the 1.55 μm window as low as 0.1-0.2 dB/cm. Singlemode waveguides can be made from these materials by photolithography or by molding. Our baseline materials, C20 and C21, are nonhalogenated polymers and exhibit waveguide losses at 1.55 μm of 1 to 1.5 dB/cm; by increasing the level of halogenation we can achieve waveguide losses as low as 0.3 dB/cm. These polymers exhibit excellent resistance to adverse environmental conditions, typified by the well-known Bellcore 85°C/85%RH soak test. 1 × 16 and 1 × 8 power splitting devices made from C20/C21 have exhibited insertion losses of 11 dB and uniformities of ± 0.3 dB at 1.3 μm. We have also invented a passive alignment technology that allows optical fibers to be "snap-fit" aligned with the optical waveguide, which reduces the difficulty and cost of pigtailing. Finally, we discuss our approach to DWDM which takes advantage of our ability to precisely control the refractive index of our polymers by proper selection of the comonomers.
- Norwood, R. A., Holman, J., Shacklette, L. W., Emo, S., Tabatabaie, N., & Guckel, H. (1998). Fast, low insertion-loss optical switch using lithographically defined electromagnetic microactuators and polymeric passive alignment structures. Applied Physics Letters, 73(22), 3187-3189.More infoAbstract: A micro-optoelectromechanical switch that combines microactuator technology developed via the Lithographie Galvanformung Abformung process with lithographically defined polymeric alignment elements is described. The multimode optical switch achieves submillisecond switching times, low insertion loss (
- Eldada, L. A., M., K., Shacklette, L. W., Norwood, R. A., Chengzeng, X. u., Chengjiu, W. u., & Yardley, J. T. (1997). Advanced polymer systems for optoelectronic integrated circuit applications. Proceedings of SPIE - The International Society for Optical Engineering, 3006, 344-361.More infoAbstract: An advanced versatile low-cost polymeric waveguide technology is proposed for optoelectronic integrated circuit applications. We have developed high-performance organic polymeric materials that can be readily made into both multimode and single-mode optical waveguide structures of controlled numerical aperture (NA) and geometry. These materials are formed from highly crosslinked acrylate monomers with specific linkages that determine properties such as flexibility, toughness, loss, and stability against yellowing and humidity. These monomers are intermiscible, providing for precise adjustment of the refractive index from 1.30 to 1.60. Waveguides are formed photolithographically, with the liquid monomer mixture polymerizing upon illumination in the UV via either mask exposure or laser direct-writing. A wide range of rigid and flexible substrates can be used, including glass, quartz, oxidized silicon, glass-filled epoxy printed circuit board substrate, and flexible polyimide film. We discuss the use of these materials on chips and on multi-chip modules (MCMs), specifically in transceivers where we adaptively produced waveguides on vertical-cavity surface-emitting lasers (VCSELs) embedded in transmitter MCMs and on high- speed photodetector chips in receiver MCMs. Light coupling from and to chips is achieved by cutting 45 degree mirrors using excimer laser ablation. The fabrication of our polymeric structures directly on the modules provides for stability, ruggedness, and hermeticity in packaging. ©2005 Copyright SPIE - The International Society for Optical Engineering.
- Eldada, L., Shacklette, L. W., Norwood, R. A., & Yardley, J. T. (1997). High-performance optical polymers for low-cost high-port-count planar wavelength-division-multiplexing devices. LEOS Summer Topical Meeting, 84-85.More infoAbstract: Wavelength division multiplexing (WDM) offers an attractive means to increase the capacity of installed optical fiber to address the ever-increasing demand for more bandwidth. Polymeric materials offer the potential to create low-cost highly complex optical interconnection circuitry on a planar substrate. They provide the possibility for a much higher degree of ruggedness and hermeticity. Polymeric waveguiding structures are very low loss, temperature resistant, humidity resistant and exhibit low dispersion and low birefringence.
- Grebel, H., Graziani, J., Vijayalakshmi, S., Shacklette, L. W., M., K., Eldada, L., Norwood, R., & Yardley, J. T. (1997). Self-imaging chirped holographic optical waveguides. Applied Optics, 36(36), 9391-9395.More infoPMID: 18264499;Abstract: To manipulate light propagation in optical waveguides, we have studied holographic, chirped structures within the waveguide's core. The holographic structures were embedded along the wave propagation direction and extended throughout the entire guide. Various self-imaging guides have been analyzed and realized to demonstrate the effect of different structures. © 1997 Optical Society of America.
- Shacklette, L. W., Norwood, R. A., Eldada, L., Glass, C., Nguyen, D., Poga, C., Baopei, X. u., Yin, S., & Yardley, J. T. (1997). Polymer optical interconnects: Meeting the requirements for datacom and telecom applications. Proceedings of SPIE - The International Society for Optical Engineering, 3147, 222-232.More infoAbstract: An advanced versatile low-cost polymeric waveguide technology has been developed for optoelectronic applications. This technology is based upon new polymeric materials for ultra-low-loss optical interconnection, particularly for the key wavelengths of 0.83, 1.3, and 1.55 microns. Development of these materials has required a thorough understanding of fundamental principles of optical absorption due to both vibrational and electronic resonant absorptions. We have thus created materials with measured losses at 830 nm which are in the range of 0.02 dB/cm. At longer wavelengths, the losses can be higher due to the vibrational absorption within the polymer. However through careful selection of chemical structure, polymeric materials with intrinsic loss below 0.08 dB/cm have been demonstrated at 1.55 micron wavelength. These high-performance organic polymers can be readily made into both multimode and single-mode optical waveguide structures with controlled numerical aperture (NA) and geometry. We will discuss the use of these materials in a variety of passive photonic devices.
- Yardley, J. T., Eldada, L. A., Stengel, K. M., Shacklette, L. W., Norwood, R. A., Chengzeng, X. u., & Chengjiu, W. u. (1997). Ultra-low-loss polymeric waveguides for optical interconnection. Proceedings of SPIE - The International Society for Optical Engineering, 3005, 155-162.More infoAbstract: AlliedSignal scientists have developed new polymeric materials for ultra-low-loss optical interconnection, particularly for the key wavelengths of 0.83, 1.3, and 1.55 microns. Developments of these materials has required a thorough understanding of fundamental principles of optical absorption due to both vibrational and electronic resonant absorptions. We have thus created materials with measure losses at 830 nm which are in the range of 0.02 dB/cm/ At longer wavelengths, the losses can be higher due to the vibrational absorption within the polymer. However through careful selection of chemical structure, polymeric materials with intrinsic loss below 0.08 dB/cm have been demonstrated at 1.55 micron wavelength. For wavelengths longer than 830 nm, single-mode and multimode waveguides with losses equal to the intrinsic loses have been fabricated.
- Chengzeng, X. u., Eldada, L., Chengjiu, W. u., Norwood, R. A., Shacklette, L. W., Yardley, J. T., & Wei, Y. (1996). Photoimageable, low shrinkage organic-inorganic hybrid materials for practical multimode channel waveguides. Chemistry of Materials, 8(12), 2701-2703.
- Dammel, R. R., & Norwood, R. A. (1996). Modeling of bottom antireflection layers: sensitivity to optical constants. Proceedings of SPIE - The International Society for Optical Engineering, 2724, 754-769.More infoAbstract: Bottom anti-reflective layers provide a number of benefits including significant reduction in swing curve amplitude and reflective notching. The key to understanding how a bottom antireflective layer improves lithography lies in the interaction of the thin film system with the exposing radiation. Bottom antireflective layers function primarily via their absorption which is significantly larger than that of the overlying photoresist at the actinic wavelength. In the simplest physical picture, a bottom antireflective layer must be thick enough to effectively extinguish radiation that has passed through it twice, with the turning point being at the substrate/bottom antireflective layer interface. It might therefore seem that the larger the bottom antireflective layer absorption coefficient, the better the performance. More precise studies show that this simplistic view is incorrect. We have modeled the general photoresist/bottom antireflective layer/substrate film stack using the standard theory of thin film optics. It follows from the complete mathematical model that at very high absorption coefficients, bottom antireflective layers may act as mirror elements of their own. Reflection from the bottom antireflective layer/photoresist interface comes both from differences in the absorption coefficients of the two materials (the dominant effect), as well as from differences in the refractive indices. Theory therefore predicts an optimum set of optical constants for every desired film thickness range, a relationship which can be summarized in simple contour diagrams.
- Eldada, L., Chengzeng, X. u., Stengel, K. M., Shacklette, L. W., Norwood, R. A., & Yardley, J. T. (1996). Low-loss high-thermal-stability polymer interconnects for low-cost high-performance massively parallel processing. International Conference on Massively Parallel Processing Using Optical Interconnections (MPPOI), Proceedings, 192-205.More infoAbstract: A versatile polymeric waveguide technology is proposed for massively parallel optical interconnections. We developed a variety of low-loss high-thermal-stability polymeric materials and used them in the fabrication of complex point-to-point optical interconnections with controlled numerical aperture (NA) and geometry. Conventional mask photolithography as well as maskless adaptive laser-based techniques were used to produce at low cost various integrated optical devices and circuits on diverse rigid and flexible substrates. Practical applications include high-speed high-density massively-parallel on-chip, chip-to-chip, on-board, board-to-board, and backplane interconnections.
- Norwood, R. A., & Whitney, L. A. (1996). Rapid and accurate measurements of photoresist refractive index dispersion using the prism coupling method. Proceedings of SPIE - The International Society for Optical Engineering, 2725, 273-280.More infoAbstract: A commercially available instrument (Metricon TM 2010) was used to perform refractive index measurements at wavelengths of 543 nm, 632.8 nm and 780 nm on AZ R photoresist and antireflection (AR) coating products. This instrument is computer-controlled and performs all analyses required to determine film indices and thicknesses. The samples were various i-line and g-line photoresists and AR coatings, spun onto silicon at thicknesses of approximately 1 - 2 microns. The reproducibility of the refractive index measurements at different spots on a given sample was found to be very high (usually less than 0.0002) and the time to measure one sample at all the wavelengths was about 15 minutes. The data were fit to a Cauchy function and low error fits were obtained. Most photoresists measured exhibited similar values for the Cauchy coefficients, while BARLi TM had much different coefficients, owing to its large absorption in the visible.
- Norwood, R. A., Eldada, L. A., Emo, S. M., Gustus, J., Rapoport, R., Stengel, K. M., Shacklette, L. W., Chengjiu, W. u., Xu, C., & Yardley, J. T. (1996). Polymer optical interconnection technology: toward WDM applications. Proceedings of SPIE - The International Society for Optical Engineering, 2690, 151-162.More infoAbstract: We have developed organic polymeric materials that can be readily made into both multimode and single-mode optical waveguide structures of controlled numerical aperture and geometry, making them excellent candidates for WDM applications. Waveguides are formed lithographically, with the liquid monomer mixture polymerizing upon illumination in the UV via either mask exposure or laser writing. Our waveguides are low loss (0.03 dB/cm at 840 nm multimode) as well as temperature resistant (up to 10 years at 120°C), enabling use in a variety of applications. Single-mode structures such as directional couplers have been made via laser writing. We further discuss the fundamental optical properties of these polymers and as they relate to WDM applications. As an example, we discuss an inorganic multimode WDM sensor that has been developed for aerospace applications and its integration with multimode polymer waveguides.
- Yamamoto, H., Funato, S., Sugiyama, T., Johnson, R. E., Norwood, R. A., Jung, J., Kinoshita, T., & Sasaki, K. (1996). Linear and nonlinear optical properties of a new organic crystal, N-(4-aminobenzenesulfonyl)acetamide. Journal of the Optical Society of America B: Optical Physics, 13(5), 837-847.More infoAbstract: A new organic crystal, N-(4-aminobenzenesulfonyl)acetamide was identified as a promismg candidate for frequency doubling to the blue region. Large square-bipyramidal single crystals up to 8 mm × 8 mm × 18 mm in size have been successfully grown by the slow-cooling technique. Optical transmission of crystal ranges from 400 to 1100 nm. The dispersions of refractive indices were measured by the minimum-deviation method. The nonlinear-optical d coefficients at 1064 nm were evaluated to be d33 = 6.2 pm/V, d31 = 3.3 pm/V, and d15 = 2.8 pm/V by the Maker-fringe technique. Type II phase matching was theoretically and experimentally demonstrated when the crystal was pumped at fundamental wavelengths between 762 and 1064 nm. Detailed characteristics of phase-matched second-harmonic generation were evaluated, along with crystal processing techniques such as cutting, polishing, and antireflection coating. © 1996 Optical Society of America.
- Yardley, J. T., Eldada, L., Norwood, R. A., Stengel, K. M., Shacklette, L. W., Chengjiu, W. u., & Chuck, X. u. (1996). Toward the practical application of polymeric interconnection technology. Molecular Crystals and Liquid Crystals Science and Technology Section B: Nonlinear Optics, 15(1-4), 443-450.More infoAbstract: Organic polymeric materials offer great promise for the creation of optical guided wave structures. We have developed a number of new polymeric materials which make possible the fabrication of complex point-to-point optical interconnections with controlled numerical aperture and geometry. Practical application for these technologies include optical backplanes, optical sensor circuitry, and high speed on-chip or chip-to-chip interconnection.
- Yamamoto, H., Funato, S., Sugiyama, T., Johnson, R. E., Norwood, R. A., Kinoshita, T., & Sasaki, K. (1995). Four-layer optical waveguide device using isopropyl-4-acetylphenylurea (IAPU). Molecular Crystals and Liquid Crystals Science and Technology Section B: Nonlinear Optics, 14(1-4), 263-272.More infoAbstract: The new organic crystal isopropyl-4-acetylphenylurea (IAPU) was identified as a promising candidate for frequency doubling to the blue light region. The nonlinear optical d-coefficient, d22 = 35 pm/V was obtained at 1064 nm by the Maker-fringe technique. The crystal's transmitting range is 380-1400 nm. Thin film of IAPU crystallize appropriately for waveguide applications. Thickness-noncritical phase-matching (TNCPM) in a four-layer waveguide structure using an IAPU crystal as a top cladding layer is proposed. Modal dispersion calculations for four-layer waveguides demonstrate the possibility of TNCPM from TE0$+ω/ mode to TE1$+2ω/ mode by adjusting the refractive indices of the two guiding layers, where the modal dispersion curves are intentionally designed to be tangent over a limited waveguide thickness. The TNCPM condition in an organic-inorganic hybrid four-layer waveguide structure is discussed as are its relaxation of tolerance requirements on waveguide fabrication.
- Chen, R. T., & Norwood, R. A. (1994). Microstructural characterization of sol-gel coating on PET films. Proceedings - Annual Meeting, Microscopy Society of America, 886-887.More infoAbstract: The ultrafine particles in the sol-gel coatings were evaluated using atomic force microscopy, a direct imaging technique. In addition, correlation of microstructures with processing parameters, coating density and other physical properties are discussed.
- Norwood, R. A., Kuzyk, M. G., & Keosian, R. A. (1994). Electro-optic tensor ratio determination of side-chain copolymers with electro-optic interferometry. Journal of Applied Physics, 75(4), 1869-1874.More infoAbstract: The paper introduces a new measurement technique called electro-optic interferometry. It is a relatively straightforward direct measurement of the electro-optic phase modulation and is related to the reflection measurement. The technique is carried out to correlate values of the electro-optic coefficients of poled polymers N-methacryloxyethyl-N-methylaminonitrostilbene/methyl methacrylate (DANS/MMA) and dicyanovinyl-hexatriene/methyl methacrylate (DCVHT/MMA). Experimental results and theoretical analysis for the measured tensor ratios r33/r13 of 3,34 for DANS/MMA and 5.9 for DANS/MMA gathered from s-p reflection technique and a reflection modified Mach-Zehnder method are presented.
- Sounik, J. R., Norwood, R. A., Popolo, J., Holcomb, D. R., & Ghatani, S. S. (1994). Silicon phthalocyanine/methyl methacrylate copolymer slab directional couplers for all-optical switching. Journal of Applied Polymer Science, 53(5), 677-685.More infoAbstract: Slab waveguide directional couplers were fabricated from the third-order nonlinear optical polymer silicon phthalocyanine/methyl methacrylate 2/98 copolymer as the active material and poly(methyl methacrylate) as the cladding layer. The monomethacrylate copolymer was synthesized, device fabrication conditions determined, and five-layer slab directional couplers fabricated. Completed couplers demonstrated waveguide loss on the order of 5 dB/cm and coupling lengths of 0.5 mm at 1.29 μm. These vertically coupled devices may be useful for all-optical switching.
- Mates, T. E., Ober, C. K., & Norwood, R. (1993). Conductivity and third-order nonlinear optical measurements of polymers with distyrylbenzene and diphenylbutadiene segments. Chemistry of Materials, 5(2), 217-221.More infoAbstract: New polymers were synthesized with discrete conjugated hydrocarbon segments alternating with flexible spacer groups. These processable polymers were designed for third-order nonlinear optical and conductivity studies for comparison with "fully-conjugated" polymers. The present materials contain distyrylbenzene or diphenylbutadiene units and have the advantages of solubility and melt processibility over "fully-conjugated" systems such as poly(acetylene). They were found in degenerate four-wave mixing experiments to have third-order optical susceptibilities in the range of 3 × 10-12 esu. These values are within an order of magnitude of the χ(3) value reported for unaligned poly(phenylenevinylene). Electrical conductivity measurements using I2 and H2SO4 dopants, however, provided materials with conductivities from 2 × 10-5 to 7 × 10-5 × 10-5 S/cm, far lower than poly(phenylenevinylene). © 1993 American Chemical Society.
- Norwood, R. A., Holcomb, D. R., & So, F. F. (1993). Polymers for nonlinear optics: Absorption, two-photon absorption and photodegradation. Molecular Crystals and Liquid Crystals Science and Technology Section B: Nonlinear Optics, 6(2), 193-204.More infoAbstract: Chromophore-incorporated polymers have been optimized with regards to their nonlinearities and thermal stabilities, but little attention has been paid to other technologically important properties of these materials. Of these, linear and nonlinear absorption at used wavelengths are of paramount importance. Linear absorption can be measured with high sensitivity for thin film polymer samples using photothermal deflection spectroscopy, as we demonstrate for (poly)methylmethacrylate. The two-photon absorption coefficient at 1300 nm of two side-chain nonlinear optical polymers is obtained, and the results are compared according to the position of the two-photon energy with respect to the known chromophore excited states. Both linear absorption and two-photon absorption can lead to photochemistry, and we examine the possibility of two-photon induced photodegradation based on photobleaching kinetics data.
- Norwood, R. A., & Sounik, J. R. (1992). Third-order nonlinear optical response in polymer thin films incorporating porphyrin derivatives. Applied Physics Letters, 60(3), 295-297.More infoAbstract: The third-order nonlinear optical properties of several porphyrin derivatives incorporated in thin films of polymethylmethacrylate have been measured by degenerate four-wave mixing at 598 nm with 1 ps pulses. Both the magnitude and dynamics of the nonlinear response are measured, with each system exhibiting both a subpicosecond response and a more slowly decaying response (10 ps-1 ns) owing to excited-state population. A copolymer of silicon phthalocyanine and methyl methacrylate exhibits a fast recovery time (15 ps) and no observable long-time (∼ns) component of its nonlinear response, as well as an absorption band twice as narrow as that of guest/host samples of the same material.
- Norwood, R. A., Sounik, J. R., Popolo, J., & Holcomb, D. R. (1991). Third-order nonlinear optical characterization of side-chain copolymers (Invited Paper). Proceedings of SPIE - The International Society for Optical Engineering, 1560, 54-65.More infoAbstract: Third order nonlinear optical properties of side-chain methacrylate copolymers incorporating 4-amino-4′-nitrostilbene, 4-oxy-4′nitrostilbene, and functionalized silicon phthalocyanine chromophores are measured by picosecond degenerate four wave mixing at 598 nm. The nonresonant stilbene system exhibits a pulse limited ultrafast response, while the resonant phthalocyanine system has a large excited state nonlinearity. Comparison of silicon phthalocyanine copolymers with solubilized guest/host systems dispersed in polymethylmethacrylate illustrate the importance of aggregation and phthalocyanine ring interaction in determining the linear optical properties and the magnitude and speed of the nonlinear optical response.
- Spangler, C. W., Saindon, M. L., Nickel, E. G., Sapochak, L. S., Polis, D. W., Dalton, L. R., & Norwood, R. A. (1991). Synthesis and incorporation of ladder polymer subunits in copolyamides, pendant polymers, and composites for enhanced nonlinear optical response. Proceedings of SPIE - The International Society for Optical Engineering, 1497, 408-417.More infoAbstract: Several electroactive polymers, such as polyacetylene, polythiophene, poly [p-phenylene vinylene] and poly [2,5-thienylene vinylene] have shown promise as NLO-active materials over the past few years. However, as several theoretical and experimental research groups have pointed out in recent publications and symposia, it is not evident that long conjugation lengths are necessary for enhanced χ(3) activity. As recently demonstrated, copolyamides which incorporate polyenylic or PTV oligomeric repeat units show χ(3)/α values of ca. 10-13 esu-cm at 532 nm(band-edge). In this paper, the authors discuss how ladder subunits related to the electroactive polymers POL and PTL can be incorporated into polymer films as (a) copolymer repeat units, (b) pendant groups attached to poly [p-hydroxystyrene] and (c) guest-host composites in polycarbonate. Sharp optical absorptions are found in all cases as well as promising χ(3) properties.
- Khanarian, G., Norwood, R. A., Haas, D., Feuer, B., & Karim, D. (1990). Phase-matched second-harmonic generation in a polymer waveguide. Applied Physics Letters, 57(10), 977-979.More infoAbstract: Quasi-phase-matched second-harmonic generation has been observed in a periodically poled nonlinear optical polymer waveguide. Key elements in this demonstration include novel nonlinear optical polymers that can be spin coated, the design and fabrication of periodic electrodes for periodic poling and the optimization of waveguide parameters to obtain single-mode waveguides with a large overlap between fundamental and harmonic modes. Phase matching of the d33 nonlinear optical coefficient occurs over a distance L=230 μm.
- Norwood, R. A., & Khanarian, G. (1990). Quasi-phase-matched frequency doubling over 5 mm in periodically poled polyme waveguide. Electronics Letters, 26(25), 2105-2107.More infoAbstract: Quasi-phase-matched second harmonic generation from 1340 to 670nm with a quasi-phase-matching length of 5 mm is demonstrated in a periodically poled polymer waveguide containing a nonlinear optical polymer. Angle, wavelength and temperature tuning are used to obtain independent measures of the quasi-phase-matching length, and those factors limiting the quasi-phase-matching length are indicated.
Proceedings Publications
- Norwood, R. A. (2017, May). Nonlinear refractive index of sulfur copolymer materials. In CLEO 2017.
- Norwood, R. A. (2017, May). Octave-spanning dual-comb spectroscopy with a free-running bidiredtional mode-locked femtosecond fiber laser. In CLEO 2017.
- Thamvichai, R., Blanche, P. A., Norwood, R. A., Wissinger, J. W., Neifeld, M. A., & Peyghambarian, N. N. (2016, 10/2016). Optical Implementation of Probabilistic Graphical Models. In Rebooting Computing (ICRC), IEEE International Conference on.
- Norwood, R. A., Cohoon, G. A., Alvarez, C. E., Meyers, K., Deheyn, D. D., Hildebrand, M., & Kieu, K. (2015, Spring). Analysis of quasi-periodic pore-network structure of centric marine diatoms. In SPIE Photonics West 2015, 9341.
- Norwood, R. A. (2012, October). Electrically tunable optical delay line in a polymer Bragg grating. In Frontiers in Optics.
- Norwood, R. A. (2014, April). Hybrid nanoarchitectured core shell plasmonic structures with tunable optical properties. In MRS Spring Meeiting, 3, 1627.
- Norwood, R. A. (2014, August). Plasmon hybridization in ITO/Ag core shell nanoarrays. In SPIE Optics and Photonics.
- Norwood, R. A. (2014, August). Plasmon-enhanced ultrathin bulk heterojunction interplay between optical and thermal responses of AuNPs. In SPIE OPTO 2014.
- Norwood, R. A. (2014, July). Fast non-blocking N x N optical switch using diffractive MOEMs. In Photonics in Switching.
- Norwood, R. A. (2014, July). Modeling of electric field enhancement in titania slot waveguides for electro-optic polymer modulators. In Integratd Photonics Research, Silicon and Nanophotonics 2014.
- Norwood, R. A. (2014, July). Mulitphoton microscopy characterization of plasmonic enhanced nanodevices. In Integrated Photonics Research.
- Norwood, R. A. (2014, July). THG as a probe for photodegradation analysis of EO polymers. In Integratd Photonics Research, Silicon and Nanophotonics 2014.
- Norwood, R. A. (2014, June). Graphene enabled 3 micron pulsed fiber lasers. In Conference for Lasers and Electro-Optics (CLEO).
- Norwood, R. A. (2014, June). Polymethines with macroscopic optical nonlinearities suitable for all-optical signal processing. In Conference for Lasers and Electro-Optics (CLEO).
- Norwood, R. A. (2014, June). Watt-level fluoride fiber lasers and amplifiers in the 1.2 micron region. In Conference for Lasers and Electro-Optics (CLEO).
- Norwood, R. A. (2014, October). Mid-IR supercontinuum generation in an integrated liquid-core optical fiber filled with CS2. In Frontiers in Optics.
- Khosroabadi, A. A., Matz, D. L., Gangopadhyay, P., Pemberton, J. E., & Norwood, R. A. (2013, Fall). Interface Between C60 and Ag on Nanostructured Plasmonic Ag Gratings: A SERS Study. In International Society for Optics and Photonics, 8809, L1-L7.
Presentations
- Norwood, R. A. (2017, January). Submicrometer thermal shifts in silicon photoni micro-ring resonators with sol-gel claddings. Photonics West 2017. San Francisco, CA: SPIE.
- Norwood, R. A. (2020, Spring). Chalcogenide hybrid inorganic/orgaanic polymers (CHIPs) based optical waveguides for integrated nonlinear photonics applications. SPIE Photonics West. San Francisco, CA: SPIE.
- Norwood, R. A. (2020, Spring). Low-loss single-mode chalcogenide hybrid inorganic/organic polymer optical waveguides for mid-wave infrared photonic applications. SPIE Photonics West 2020. San Francisco, CA: SPIE.
- Norwood, R. A. (2020, Summer). Optical polymer solar concentrators for compact CPV systems. CPV-16. Denver, CO: AIP.
- Norwood, R. A. (2019, Spring). High sulfur content photo-bleached polymer waveguides for mid-infrared optical applications. SPIE Photonics West. San Francisco, CA: SPIE.
- Norwood, R. A. (2019, Spring). High-speed read-out of cryogenic focal plane arrays. GoMacTech 2019. GoMacTech: DoD.
- Norwood, R. A. (2019, Spring). Polymer optical interconnects for silicon and silicon nitride photonics. SPIE Photonics West. San Francisco, CA: SPIE.
- Norwood, R. A. (2019, Spring). Polymeric infrared antireflection coating for silicon substrates. SPIE Photonics West 2019. San Francisco, CA: SPIE.
- Norwood, R. A. (2019, Summer). Sulfur and selenium-based polymers for infrared optics and photonics. Novel Optical Materials and Applications. San Francisco, CA: OSA.
- Norwood, R. A. (2018, Spring). High-reflectivity Bragg mirrors for IR applications using novel chalcogenide hybrid inorganic/organic polymers (CHIPs). SPIE Photonics West 2019. San Francisco, CA: SPIE.
- Norwood, R. A. (2018, Spring). Optical Sciences: Engine of the Information Age. University of Arizona Materials Science and Engineerig Colloquium. Tucson, AZ: UA Materials Science and Engineering Department.
- Norwood, R. A. (2018, Spring). Optical Sciences: Engine of the Information Age. University of North Texas Physics Colloquium. Denton, Texas: University of North Texas.
- Norwood, R. A. (2018, Spring). Relaxed tolerance adiabatic silicon nitride coupler for high I/O port-density optical interconnects. SPIE Photonics West 2018. San Francisco: SPIE.
- Norwood, R. A. (2018, Spring). Understanding complexity in mode-locked fiber lasers. SPIE Photonics West 2018. San Francisco, CA: SPIE.
- Norwood, R. A. (2018, Sujmer). Low-loss etchless photodefined polymer optical waveguides. CLEO 2018. San Jose, CA: OSA.
- Norwood, R. A. (2017, January). Relaxed tolerance adiabatic silicon coupler for high I/O port density optical interconnects. Photonics West 2017. San Francisco, CA: SPIE.
- Norwood, R. A. (2016, 2016). SESAM Q-switched fiber laser at 1.2 micron. CLEO. San Jose, CA: Optical Society of America.
- Norwood, R. A. (2016, August). Mechanisms for reciprocity failure in photorefractive polymers. SPIE Optics and Photonics. San Diego, CA: SPIE.
- Norwood, R. A. (2016, August). Nanocomposites and nanostructured materials for integrated photonics. Telluride Nanomaterials Meeting. Telluride, CO: Telluride Summer Topical Meetings.
- Norwood, R. A. (2016, August). Ultrahigh refractive index chalcogenide based copolymers for infrared optics. SPIE Optics and Photonics. San Diego, CA: SPIE.
- Norwood, R. A. (2016, February). Dual-comb spectroscopy with a free-running bidirectionally mode-loked fiber laser. SPIE Photonics West. San Francisco: SPIE.
- Norwood, R. A. (2016, February). Femtosecond laser written microresonators and nanophotonic circuitry. SPIE Photonics West. San Francisco, CA: SPIE.
- Norwood, R. A. (2016, February). Second- and third-harmonic generation microscopy of layered molybdenum disulfide. SPIE Photonics West. San Francisco, CA: SPIE.
- Norwood, R. A. (2016, February). Ultrahigh refractive index chalcogenide based copolymers for infrared optics. SPIE Photonics West. San Francisco, CA: SPIE.
- Norwood, R. A. (2016, June). Direct comparison of second and third harmonic generation in mono- and few-layer MX2 by multiphoton microscope. CLEO. San Jose, CA: Optical Society of America.
- Norwood, R. A. (2016, June). Power scalingof single-frequency fiber amplifiers at 976nm. CLEO. San Jose, CA: Optical Society of America.
- Norwood, R. A. (2016, June). Real-time dual-comb spectroscopy with a free-running femtosecond fiber laser. CLEO. San Jose, CA: Optical Society of America.
- Norwood, R. A. (2016, March). Passive athermal silicon ring resonators with sol-gel claddings. Optical Fiber Communications Conference. Los Angeles, CA: Optical Society of America.
- Norwood, R. A. (2016, September). Integrated photonics: The right tool for more jobs. Raytheon Engineers On the Go Series. Tucson, AZ: Raytheon.
- Norwood, R. A. (2016, Summer). Ultra high refractive index polymers for IR optics. NOMA. Vancouver, BC: Optical Society of America.
- Norwood, R. A., Blanche, P. A., Lynn, B., & Peyghambarian, N. (2015, Summer). Advances in photorefractive polymers and applications. SPIE Optics and Photonics 2015. San Diego, CA: SPIE.
- Norwood, R. A., Churin, D., Olson, J., Peyghambarian, N., & Kieu, K. (2015, Spring). High power synchronously pumped femtosecond Raman fiber laser. CLEO 2015. San Jose, CA: OSA.
- Norwood, R. A., Gowda, R., Nguyen, N., Diels, J. C., Peyghambarian, N., & Kieu, K. (2015, Spring). All-fiber bidirectional optical parametric oscillator for precision rotation sensing. CLEO 2015. San Jose, CA: OSA.
- Norwood, R. A., Karvonen, L., Saynatjoki, A., Mehravar, S. S., Rodriguez, R. D., Hartmann, S., Zahn, D. R., Honkanen, S. K., Peyghambarian, N. N., Kieu, K., Lipsanen, H., & Riikonen, J. (2015, Spring). Optical nonlinearities in few-layer gallium selenide. SPIE Photonics West 2015. San Francisco, CA: SPIE.
- Norwood, R. A., Kim, K. J., Herrera, O. D., Namnabat, S., Himmelhuber, R., Luo, J., & Jen, A. K. (2015, Spring). Determination of thermo-optic characteristics in electro-optic polymer materials based on polymer Bragg grating waveguides. SPIE Photonics West 2015. San Francisco, CA: SPIE.
- Norwood, R. A., Miles, A., Gangopadhyay, P., Gai, Y., Wang, X., & Watkins, J. J. (2015, Spring). Verdet constant and magnetic permeability in microstructured FePt nanoparticles in PS-P2VP copolymer composite films. CLEO 2015. San Jose, CA: OSA.
- Norwood, R. A., Perry, J. W., Adibi, A., Barlow, S., Bredas, J. L., Eftekhar, A. A., Getmanenko, Y., Gieseking, R. L., Hales, J. M., Hosseinnia, A. H., Kieu, K., Kim, H., Marder, S. R., Maredinejad, H., Risko, C. M., Shahin, S., & Zhang, Y. (2015, Spring). Processable organic materials with large figures-of-merit for all-optical signal processing. SPIE Photonics West 2015. San Francisco, CA: SPIE.
- Norwood, R. A., Saynatjoki, A., Karvonen, L., Riikonen, J., Kim, W., Makinen, J., Mehravar, S., Peyghambarian, N., Lipsanen, H., & Kieu, K. (2015, Spring). Third harmonic generation and multiphoton fluorescence in graphene using a compact femtosecond 1.56 micron laser. SPIE Photonics West 2015. San Francisco, CA: SPIE.
- Norwood, R. A. (2014, April). Advances in organic nonlinear photonics. College of Optical Sciences Colloquium. Tucson, AZ: College of Optical Sciences, University of Arizona.
- Norwood, R. A. (2014, April). Charge transfer mechanism at the interface of C60/Ag nanostructures. MRS Spring Meeting 2014. San Francisco, CA: Materials Research Society.
- Norwood, R. A. (2014, April). Spectroscopic ellipsometry study of ITO/Ag hybrid nanorod layers for plasmonic solar cell applications. E-MRS 2014 Spring Meeting 26-30. Lille, France.
- Norwood, R. A. (2014, August). Nanophotonics materials and devices: driving the big data engine. SPIE Optics and Photonics. San Diego, CA.
- Norwood, R. A. (2014, February). Hybrid metal/semiconductor nanostructured coatings for plasmonic solar cells studied by spectroscopic ellipsometry. Photovoltaic Technical Conference - Thin Film & Advanced Silicon Solutions. France.
- Norwood, R. A. (2014, February). Label-free multiphoton imaging using a compact femtosecond fiber laser mode-locked by carbon nanotube saturable absorber. SPIE Photonics West 2014. San Francisco, CA: SPIE.
- Norwood, R. A. (2014, February). Microsecond reconfigurable NxN data communication switch using DMD. SPIE Photonics West 2014. San Francisco, CA: SPIE.
- Norwood, R. A. (2014, February). Microsecond regime free-space fiber optic switch: 32-port to 32-port scalable device. SPIE Photonics West 2014. San Francisco, CA: SPIE.
- Norwood, R. A. (2014, February). Multiphoton excitation of organic chromophores in microbubble resonators. SPIE Photonics West 2014. San Francisco, CA: SPIE.
- Norwood, R. A. (2014, February). Nanolaminate structures fabricated by ALD for reducing propagation losses and enhancing the third-order optical nonlinearities. SPIE Photonics West 2014. San Francisco, CA: SPIE.
- Norwood, R. A. (2014, February). Optical properties of sulfur copolymers for infrared applications. SPIE Photonics West 2014. San Francisco, CA: SPIE.
- Norwood, R. A. (2014, February). Silicon/electro-optic polymer hybrid directional coupler switch. SPIE Photonics West 2014. San Francisco, CA: SPIE.
- Norwood, R. A. (2014, February). Thermal emitter performance as a function of lithographic quality. SPIE Photonics West 2014. San Francisco, CA: SPIE.
- Norwood, R. A. (2014, February). Wide spectral range ellipsometric study of nanostructured ITO layers by node spline method. 8th Workshop on Ellipsometry. Dresden, Germany.
- Norwood, R. A. (2014, January). Hybrid polymer photonic materials and devices for optical communications and RF photonics. Materials Science Symposium, University of Washington. University of Washington, Seattle, WA: Materials Science and Engineering Department, University of Washington.
- Norwood, R. A. (2014, June). Organic electro-optic materials and devices: Molecular engineering driving device performance and technology innovation. Conference for Lasers and Electro-Optics (CLEO). San Jose, CA: Optical Society of America (OSA).
- Norwood, R. A. (2014, March). Electro-optic polymers and their role in silicon photonics. CIAN Lecture Series. Tucson, AZ: CIAN Center.
Poster Presentations
- Norwood, R. A. (2019, Spring). Presentation of novel t-BoC protected styrenic sulfides with phototunable refractive indices for integrated optics. SPIE Photonics West 2019. San Francisco, CA: SPIE.
- Norwood, R. A. (2016, February). Surface-enhanced Raman scattering in C. wailesii diatom frustules. SPIE Photonics West. San Francisco, CA: SPIE.