In_xGa_(1-x)N/GaN量子阱在时间分辨简并四波混频中的量子拍特性  

Characteristics of Quantum Beat of Degenerated Four-Wave Mixing in In_xGa_(1-x)N/GaN Quantum Well

作　　者：李琪[1] 熊贵光[1] 

机构地区：[1]武汉大学物理科学与技术学院,湖北武汉430072

出　　处：《武汉大学学报（理学版）》2005年第3期291-294,共4页Journal of Wuhan University:Natural Science Edition

基　　金：国家自然科学基金项目(10474076)

摘　　要：基于激光与物质相互作用的半经典理论,采用布洛赫方程,分析了在时间分辨简并四波混频条件下,InxGa1-xN/GaN量子阱中轻空穴激子和重空穴激子的量子相干特征.理论计算表明,时间分辨四波混频中的探测信号受时间调制,具有典型的量子拍特征,拍频周期随InxGa1-xN/GaN量子阱中In含量的增加而增大,当x=0.125时,拍频周期为120fs,当x=0.25时,拍频周期为180fs.信号的强度和振荡的幅值与阱材料的光学极化退相率有关,随着退相率的减小而显著增强,结合量子阱材料中的量子约束效应,对退相率和信号强度的关系进行了分析.Based on the quasi-classical theory on the interaction of laser and matter,the characteristics of heavy and light-hole quantum beat of degenerated four-wave mixing in In_xGa_(1-x)N/GaN quantum well have been analyzed by solving the Bloch equations. The model used for describing the phenomena can be considered as a three-level system consisting of the ground state and two excited states from which the wave packet is formed and the model is a Λ-type system. It is shown that the intensity of the oscillation detected in degenerated four-wave mixing is modulated with real time and has the typical characteristics of quantum beat. The period of the beat increase with the increase of In content (x).When x=0.125,the period is 120 fs and when x=0.25,the period is 180 fs.The intensity and the amplitude of the oscillation of the sighal have great dependence on the dephasing rate of the quentum well and increase with the derease of the dephasing rate.

关 键 词：时间分辨四波混频 量子阱 量子拍 退相率 

分 类 号：O472.3[理学—半导体物理]