随机激光中环形随机腔的谐振特性分析

采用时域有限差分法(FDTD)直接求解Maxwell方程组,分析了二维随机激光器中环形随机腔的构成、形成条件及光波模式特性等.计算表明:随机激光器中形成环形随机腔的散射体临界浓度为30%;随机腔中模式数随散射体粒径增大而增加,且光波模式向低频方向漂移;模式频率间隔只受散射体粒径影响而与散射体浓度(占容比)无关,粒径增大时频率间隔变小;模式特征与散射体的类型无关,最优散射体折射率在2左右.由计算结果可知,可以根据增益介质的特性来选择散射体的参数以得到随机激光的最佳输出特性.

Resonance Characteristics of Loop Random Cavities in Random Laser

A finite-difference time-domain(FDTD) method is used to solve Maxwell's equations directly.We have studied the structure,condition of formation and mode characteristic.The number of mode in random cavity increases but the mode interval decreases with the increase of the scatterer radius and the mode drifts to low frequency.The intensity of mode attenuates with the decrease of scatterer density,but there is nearly no resonance mode in random cavity when the density is lower than 30%.The mode interval is influenced most strongly by the radius and is not subject to the density.The mode characteristic in random cavity is independent of categories of scatterer and the optimum refractive index is about 2.According to the results,the optimum output of random laser can be obtained by designing the parameters of scatterer based on the properties of the gain medium.