双量子阱中的子带光吸收

由于微制造技术的不断发展，如液相外延(LPE)，气相外延(VPE)，金属有机化学气相沉积(MOCVD)以及分子束外延技术(MBE)等先进的材料生长技术方法也日趋完善，从而使得各种低维半导体量子器件(如半导体、超晶格、量子阱、量子线和量子点等)制造日趋成熟。由于这些低维半导体量子器件具有很强的非线性光效应，而且随着材料、外形、尺寸等的不同，非线性光效应也有很大的差别，更由于其可能存在的广泛的应用前景，所以近年来，一直是人们研究的重点。近来，由于人们相信，利用GaAs／AlGaAs量子阱有可能制造出一些新型的光学仪器，如光开关、光限幅器、光调制器等，所以，对不同势形的GaAs／AlGaAs量子阱的非线性光学特性一直吸引着人们进行理论和实验的研究。而在最近几年，对双量子阱的研究也成为了人们的研究重点。通过密度矩阵和迭代的方法，得到双量子阱中的第一、第三阶子带光吸收表达式，我们将用一个典型的GaAs／AlGaAs双量子阱代入其中进行数值计算，并进行讨论。我们的计算结果显示，阱的光吸收峰不但与中间的势垒宽度有关，更与入射光强有关。

Intersubband Optical Absorption in Double Quantum Wells

Recently, much attention has been focus on the investigation of the electroabsorption in the GaAs/AlGaAs quantum wells (QW's) because of its possibility of designing new types of electro-optic modulators. Much optical properties of the single QW's with different potential has been and being investigated experimently and theoriticaly with different methods. In these few years, the double quantum wells (DQWs) became the focus of the research. In this paper, by using the density matrix formalism and iterated method, the first-and the third-order intersubband optical absorption of double quantum well with infinit boundary was investigated theoretically. Thereafter, a typical GaAs/AlGaAs DQWs is presented to get the results. The results show that the peak absorption varies with the width of the intermediate potential barrier. And it also shows that the absorption decrease as the incident optical intensity increasing.