Theory of light diffusion in disordered media with linear absorption or gain
Theory of light diffusion in disordered media with linear absorption or gain
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DOI：
10.1103/physrevb.71.184201
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发表时间：
2005-05-01
影响因子：
3.7
通讯作者：
Busch, K
中科院分区：
文献类型：
--
作者：
Lubatsch, A;Kroha, J;Busch, K
我们提出了一个详细的，微观输运理论的光在强散射无序系统的组成材料表现出线性吸收或增益。从麦克斯韦方程组出发，我们推导出传输量的一般表达式，如能量传输速度，传输平均自由程，扩散系数和吸收/增益长度。该方法是基于一个完全矢量的广义动力学方程的治疗，并利用一个确切的沃德身份（WI）。而对于无损耗和无增益的介质，WI反映了局部能量守恒，吸收或相干增益的影响完全由WI中的附加项来实现。由于共振（米氏）散射的结果，从各个散射体，所有的运输量获得强的，频率相关的重正化，这是，此外，特征修改吸收或增益。我们说明了这些quantities的稀释系统的各种实验参数的影响。这里提出的输运理论可以为三维无序介质中的随机激光理论奠定基础。
We present a detailed, microscopic transport theory for light in strongly scattering disordered systems whose constituent materials exhibit linear absorption or gain. Starting from Maxwell's equations, we derive general expressions for transport quantities such as energy transport velocity, transport mean free path, diffusion coefficient, and absorption/gain length. The approach is based on a fully vectorial treatment of the generalized kinetic equation and utilizes an exact Ward identity (WI). While for loss- and gainless media the WI reflects local energy conservation, the effects of absorption or coherent gain are implemented exactly by additional terms in the WI. As a result of resonant (Mie) scattering from the individual scatterers, all transport quantities acquire strong, frequency-dependent renormalizations, which are, in addition, characteristically modified by absorption or gain. We illustrate the influence of various experimentally accessible parameters on these quanitities for dilute systems. The transport theory presented here may set the stage for a theory of random lasing in three-dimensional disordered media.