一维随机介质中准态模式的局域化程度对其阈值的影响

基于将Maxweil方程与四能级原子系统速率方程相结合而建立起的随机激光时域理论,并利用有限时域差分法,研究了一维随机激活介质中激光模式的输出强度与抽运速率之间的关系.结果表明,与传统激光模式相似,随机激光模式的强度随抽运速率的变化不仅具有阈值特性,而且具有饱和特性.用模式的空间区域来表征模式的局域化程度,发现局域化程度越强的模式,阈值越低.不过,这种关系不是一一对应的.这表明模式的局域化程度是决定阈值大小的重要因素,但不是唯一的因素.

Influence of Spatial Localization on Lasing Threshold of Quasi-State Mode in One-Dimension Random Media

Based on the time dependent theory of random lasers, which was built via combining Maxwell equations with the rate equations of a four-level atomic system, the output intensity of a lasing mode varying with the pumping rate is simulated for a two-dimensional random active medium by use of the finite difference time domain method. Results show that the pumping rate dependence of the output intensity presents not only a threshold property, but also a saturation property, just like that of lasing modes in conventional lasers. Charactering the mode's localization extent via the mode's area indicates that the stronger the mode's localization extent is, the lower the mode's threshold is. However, such a relation is not a one-to-one correspondence, meaning that the mode's localization extent is an important fact to determine the mode's threshold, but is not alone.