Femtosecond Optics of Quantum Confined Materials and Devices

这个项目是针对量子的基本理解 受限半导体光学非线性及其演示 高速全光器件。 这些材料将 在这个项目下研究的是硒化镉和镉 硫化物量子点和GaAs -Al GaAs多量子威尔斯阱。 通过 量子点，研究人员指的是半导体的微晶 嵌在玻璃基质中， 比激子玻尔半径具有更均匀的尺寸分布。 他们将彻底调查的规模和反应时间， 这些量子点的光学非线性， 数量及其批量值，将使他们能够确定 量子点中的量子限制是否会导致 材料的非线性或速度。 瞬时非线性 激子光学斯塔克效应所产生的， 演示GaAs MQW定向耦合器中的高速开关。 最后，他们将尝试产生亚皮秒电脉冲， 使用虚拟载波激励，然后使用这些超短 在MQW非线性中获得亚皮秒开关的电脉冲 定向耦合器通过量子限制斯塔克效应。

This project is directed towards basic understanding of quantum confined semiconductor optical nonlinearities and demonstration of high-speed all-optical devices. The materials that will be investigated under this program are Cadmium Selenide and Cadmium Sulfide quantum dots and GaAs - A1GaAs multiple quantum wells. By quantum dots, the investigators mean microcrystals of semiconductor embedded in glass matrices with sizes that are comparable or smaller than the exciton Bohr radius with a more uniform size distribution. They will investigate thoroughly the magnitude and response time of optical nonlinearity in these quantum dots and compare these quantities with their bulk values, will enable them to determine whether quantum confinement in the dots results in enhancement of the nonlinearity or speed of the material. The instantaneous nonlinearity arising from exciton optical Stark effect will be employed to demonstrate high-speed switching in a GaAs MQW directional coupler. Finally, they will attempt to generate subpicosecond electrical pulses using virtual carrier excitation, and then use these ultrashort electrical pulses to obtain subpicosecond switching in a MQW nonlinear directional coupler via the quantum confined Stark effect.