Yamilov A, Wu X, Cao H, Burin A L
Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, USA.
Opt Lett. 2005 Sep 15;30(18):2430-2. doi: 10.1364/ol.30.002430.
We present a numerical study of lasing modes in diffusive random media with local pumping. The reabsorption of emitted light suppresses the feedback from the unpumped part of the sample and effectively reduces the system size. The lasing modes are dramatically different from the quasi modes of the passive system (without gain or absorption). Even if all the quasi modes of a passive diffusive system are extended across the entire sample, the lasing modes are still confined in the pumped volume with an exponential tail outside it. The reduction of effective system volume by absorption broadens the distribution of decay rates of quasi modes and facilitates the occurrence of discrete lasing peaks.
我们对具有局部泵浦的扩散随机介质中的激光模式进行了数值研究。发射光的再吸收抑制了样品未泵浦部分的反馈，并有效地减小了系统尺寸。激光模式与无源系统（无增益或吸收）的准模式有显著不同。即使无源扩散系统的所有准模式都扩展到整个样品，激光模式仍局限于泵浦区域，在其外部有指数衰减的尾部。吸收导致有效系统体积减小，拓宽了准模式衰减率的分布，并促进了离散激光峰的出现。
