9412772 Boyd The principle aspects of the proposed research are the fabrication of quantum wires, optical channel waveguides, and microcavity structures and optical characterization of their properties. FIB- induced compositional mixing of MQW regions will be a primary fabrication technique, while time-resolved and spatially-resolved photoluminescence is the main technique to be performed for evaluating the quality of these structures. Since these nanostructures are directed at enhancing nonlinear optical interactions and improving semiconductor laser performance, we expect to characterize nonlinear optical effects resulting from quantum wires and microcavities and to determine the impact of FIB- fabricated microcavity structures on semiconductor lasers. Microcavity structures are finding advantageous use in vertical cavity surface emitting lasers (VCSELs) and have considerable potential for the formation of Fabry-Perot bistable switches. As a part of the proposed research, we will be applying FIB processing capability to the fabrication of these structures. The direct write capability of FIB processing (mixing and milling) is expected to provide significant improvement in device isolation and pn junction formation. The high resolution properties (~50 nm) of the FIB system and its capability to direct write patterns onto samples will allow us to fabricate several waveguide structures which will elucidate nonlinear optical effects, including nonlinear distributed feedback gratings, directional couplers, and Mach-Zehnder interferometers. We expect to demonstrate all-optical switching with these structures which will be characterized by low switching powers. ***
