半导体量子阱中激子波函数及其 Fourier系数的计算和应用

利用准玻色子方法发展的激子动力学方程是研究半导体纳米结构中激子超快动力学的有效理论手段. 为了将这种方法应用于半导体量子阱, 需要知道量子阱中的激子波函数及其在动量空间的表示, 从而得到激子动力学方程中所必须的系数. 详细讨论了理想和实际量子阱中的激子波函数, 特别是其在动量空间的表示, 并进一步讨论了激子动力学方程中所必须系数的计算方法. 通过求解这些系数, 对量子阱中因激子密度变化而引起的太赫兹脉冲作用下激子能级间跃迁过程中的非线性效应进行了理论预测, 得到了与实验符合很好的结果.

Wavefunction and Fourier coefficients of excitons in quantum wells: computation and application

Excitonic dynamic equations, which are derived from the quasi-Boson approach, are useful tools in investigating the ultrafast optical responses of semiconductor nanostructures. To apply these equations to the exciton dynamics in semiconductor quantum wells, we need exciton wavefunctions and their representations in momentum space to obtain the coefficients in the excitonic dynamic equations. By discussing in detail the exciton wavefunctions and their momentum-space representations, we present a method of obtaining the essential coefficients in the excitonic dynamic equations. We finally use these coefficients to understand the nonlinear effects in the terahertz-pulse-induced intraexcitonic transitions caused by high exciton densities. The obtained theoretical results are in good agreement with recent experimental results.