金属-半导体复合纳米结构的光学双稳特性是非线性光学的研究热点之一，在纳米功能器件的设计方面具有很大的潜在应用价值，然而复合纳米结构的光学双稳机理尚不明确。本项目拟采用理论计算和实验证明相结合的方法，针对金属-半导体复合纳米结构的光学双稳机理展开深入研究。在理论上用解析法推导在实际情况下金属-半导体复合纳米结构在强泵浦场和弱探测场作用下的激子粒子数和非线性吸收系数表达式，研究光学双稳产生的一般条件，给出结构参量、激发条件等因素与激子粒子数和非线性吸收双稳阈值的关系；在理论指导下，制备金属-半导体复合纳米结构样品，利用高分辨率的泵浦-探测测试系统验证样品的光学双稳态。通过理论和实验研究，阐明复合纳米结构的光学双稳机理，提出光学双稳的调控方法，为基于光学双稳的量子器件的设计提供科学依据。

Optical bistability in hybrid metal-semiconductor nanostructures is a hot area of research in nonlinear optics, which promises various potential applications in the field of designing nanoscale functional devices. However, the mechanism of optical bistability in hybrid nanostructures is yet undefined. The project intends to investigate intensively the mechanism of optical bistability in hybrid metal-semiconductor nanostructures by theoretical calculations and experiments. We will duduce the formulas of exciton population and nonlinear absorption coefficient of hybrid metal-semiconductor nanostructures under a strong pump field with a weak probe field in the practical case by using an analytical method, investigate the analytical bistability condition and obtain the relationships between the bistability thresholds for exciton population and induced nonlinear absorption and some physical factors such as structural parameters and excitation conditions; under the guidance of this theory, metal-semconductor hybrid nanostructures are prepared experimentally and the bistability of the samples can be demonstrated by using a pump-probe technique. Through the theoretical and experimental investigations, the mechanism of optical bistability in hybrid metal-semiconductor nanostructures will be revealed, and the methods for adjusting the optical bistability will be proposed, which provide a scientific basis for designing quantum devices based on optical bistability.