We performed Mueller matrix Monte Carlo simulations of the propagation of optical radiation in diffusely scattering media for collimated incidence and report the results as a function of thickness and the angle subtended by the detector. For sufficiently small thickness, a fraction of the radiation does not undergo any scattering events and is emitted at zero angle. Thus, for a very small detector angle, the measured signal will indicate mostly the attenuation of the coherent contribution, while for larger angles, the diffuse scattering radiation will contribute significantly more. The degree to which the radiation is depolarized thus depends on the angle subtended by the detector. A three-stream model—where the coherent radiation, the forward diffusely scattered radiation, and the backward scattered radiation are propagated according to the differential Mueller matrix formalism—is introduced and describes the results from the Monte Carlo simulations and the results of measurements well. This scatter-based model for depolarization in diffusely scattering media is an alternative to that based upon elementary fluctuation theory applied to a single propagation stream. Results for average photon path length, determined from the Monte Carlo simulations, suggest that applying fluctuation theory to photon path length may unify the two approaches.

中文翻译：

---

漫散射介质中透射去偏振的演变。


我们对准直入射的漫散射介质中光辐射的传播进行了穆勒矩阵蒙特卡罗模拟，并将结果报告为厚度和探测器所对角度的函数。对于足够小的厚度，一部分辐射不会经历任何散射事件并以零角度发射。因此，对于非常小的探测器角度，测量的信号将主要指示相干贡献的衰减，而对于较大的角度，漫散射辐射的贡献将显着更大。因此，辐射去偏振的程度取决于检测器所对的角度。引入了三流模型，其中相干辐射、前向漫散射辐射和后向散射辐射按照微分穆勒矩阵形式传播，并很好地描述了蒙特卡罗模拟的结果和测量结果。这种基于散射的漫散射介质去极化模型是基于应用于单个传播流的基本波动理论的替代模型。根据蒙特卡罗模拟确定的平均光子路径长度的结果表明，将涨落理论应用于光子路径长度可以统一这两种方法。