量子点量子阱中的三阶非线性光学特性的研究

利用紧致密度矩阵近似方法，研究了一个特殊量子点量子阱中的三阶非线性光学特性(三次谐波产生)，得到了量子点量子阱系统的三次谐波产生系数的解析表达式，而且考虑了量子点量子阱系统中的两种电子束缚态-壳层阱内与阱外两种束缚态。对CdS/HgS构成的典型的量子点量子阱进行了数值计算，得到了10^-15(m／v)^2量级的三次谐波产生系数，并且绘出了三次谐波产生系数作为量子点量子阱的尺寸和泵浦光子能量的函数曲线，最后对曲线的特征及其形成的原因进行了解析。

Studies on the Third-order Nonlinear Optical Properties of a Quantum Dot Quantum Well

The third-order nonlinear optical properties of a quantum dot quantum well (QDQW) are theoretically investigated. The analytic formula for the third-harmonic generation (THG) coefficient of a QDQW is obtained by using compact density matrix treatment, both the bound electronic states inside and outside the spherical shell well are taken into account. The numerical results are carried out on the classic CdS/HgS QDQW, and the THG coefficient reaches the magnitude of 10-15 (m/V)2. Finally, the THG coefficient is plotted versus the QDQW size, the photon energy, and the features of these curves are specified and the reasons are explained.