二维随机介质中模式的空间局域化分布

Spatial Localized Distribution of Modes in Two-Dimension Random Medium

基于随机激光的时域理论,利用时域有限差分法(FDTD)数值求解麦克斯韦方程组和速率方程组,利用分区域计算法,分别计算了整体和局部泵浦二维随机介质时,不同泵浦强度下,不同区域的辐射谱,得出了随机介质中模式的空间局域化分布。计算结果显示,同样条件下不同区域的辐射谱是不同的,且随着激励源泵浦强度的变化,随机激光辐射始终集中在介质中某几个固定区域,但各个区域的随机激射效率不同,在区域之间存在模式的空间范围重叠。利用该方法,可以分析介质的随机分布对随机激射的影响,理论上可以为高激射效率的伪随机介质制备提供一定指导。

Based on the time dependent theory, FDTD algorithm was used to numerically solve Maxwell＇s equations and rate equations. By dividing the two-dimension random medium, the emission spectra of different region under different pumping intensities were obtained. The calculated results show that the emission spectra of different region are different, the energy of emission is mainly distributed in some certain region, and the pumping efficiency is different. Also spatial extent overlap of modes is reproduced. With this method, the dependence of random distribution on lasing can be analyzed and it should be useful for the preparation of pseudo-random medium.