Optical Devices Research Group

Professor Garmire's research group is currently composed of ten PhD students. Collaborations are currently underway with Lute Maleki from JPL, Alan Kost and Tom Hasenberg from Hughes Research Laboratories.

The research interest of the group are broadly based in the areas of nonlinear optics, integrated and fiber optics, semiconductor lasers and infrared detectors. Applications envisaged for such devices range from optical computing and neural nets to optical communications and frequency standards.

• Nonlinear Optical Properties of Semiconductors: Nonlinear absorption and nonlinear refractive index are studied in semiconductors: InAs, GaAs, and CdZnSe. Investigations are made with lasers tuned to near the bandgap using either nonlinear transmission or pump-probe techniques. Special emphasis is placed on layered media such as multiple quantum wells, Bragg reflectors, n-i-p-i structures and depletion layers.

• Applications: Nonlinear materials in surface-normal configurations are being explored for advanced Spatial Light Modulators, optical bistable switches, phase modulators and fast, high contrast SLM's. Other applications demonstrated include Q-switching of YAG lasers. New concepts have been developed for improved far-infrared focal plane detector arrays.

• Photorefractive Effect: Studies of enhanced two-wave mixing in near the band-edge in GaAs and other semiconductors have been explored, particularly for phase-conjugate resonators. Studies have also been made of the photorefractive effect and fixing gratings in LiNbO3 waveguides.

• Semiconductor Lasers: GaAs laser arrays in properly designed external cavities provide power diffraction limited output. Temporal mode-locking provides psec pulses. Both systems have been investigated both experimentally and theoretically, as well as basic nonlinear optical phenomena in such systems such as frequency-locking and chaos. Long-wavelength lasers, planned to operate in the 3 µ m wavelength region have been explored, as well as double carrier confinement lasers operating at 1.3 µ m were built.

• Integrated Optics: Semiconductor modulators and bistable devices, LiNbO3 modulators, polymer films and couplers, and a ring interferometer have been fabricated in our clean room and fully characterized. Quasi-phase matching for harmonic generation is presently being studied.

• Fiber Optics: Recent studies entail fiber monitoring of bridges, power-by-light down a fiber, combined spatial-temporal CDMA systems, color center formation in UV fibers, a study of the simulated Raman effect in fibers, and hollow metal waveguides for far infrared.

USC Home Page   Home Page of Center for Laser Studies