Design And Fabrication Of Optically-pumped Guided-mode Resonance Surface-emitting Lasers
Young, Preston Phillip
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This dissertation describes the design and fabrication of guided-mode resonance (GMR) structures and their applications to laser devices. These include tunable Ti:Sapphire lasers as well as semiconductor lasers with integrated light emitting layers. The resonance characteristics of GMR structures are determined by the designed and fabricated waveguide-grating parameters. The primary tool for the design and simulation analysis of GMR devices is rigorous coupled-wave analysis (RCWA). This numerical method is used to provide diffraction efficiency calculations as well as simulations of the electric fields within GMR structures. RCWA-based field analysis is used to design an optically pumped GMR surface-emitting laser (GMR-SEL) in the GaAs/AlxGa1-xAs material system with an In0.2Ga0.8As quantum well for output wavelength near 980 nm. All optical GMR devices require patterning of sub-micron diffraction grating structures. Preliminary GMR grating fabrication is performed by holographic interference lithography and is optimized by utilizing a charge-coupled device (CCD) camera-based fringe stabilization system. Prototype GMR-SEL devices are fabricated in the GaAs/AlxGa1-xAs material system by electron-beam lithography and reactive-ion etching (RIE). Electron-beam lithography is performed using hydrogen silsesquioxane (HSQ) as high-resolution resist material. The results of exposure proximity correction for electron-beam lithography are presented. An RIE process suitable for reliable etching of the HSQ grating patterns into a semiconductor GMR-SEL wafer is developed and characterized. The fabricated prototype GMR-SEL devices are optically pumped at an oblique GMR resonance angle near 45º corresponding to the 810 nm output of a Ti:Sapphire laser. Whereas these elements have insufficient gain for lasing, the measured photoluminescence spectra for several devices exhibit spectral peaks that occur precisely at the theoretical GMR-SEL resonance locations. Therefore, this dissertation provides results and methods useful to experimentally realize prototype GMR-SEL devices fabricated in semiconductor materials.