Muinonen Karri, Markkanen Johannes, Väisänen Timo, Peltoniemi Jouni, Penttilä Antti
Opt Lett. 2018 Feb 15;43(4):683-686. doi: 10.1364/OL.43.000683.
We consider the scattering and absorption of light in discrete random media of densely packed spherical particles. In what we term "radiative transfer with reciprocal transactions" (RT), we introduce a volume element of the random medium, derive its scattering and absorption characteristics using the superposition T-Matrix method (STMM), and compute its frequency-domain incoherent volume-element scattering characteristics. Using an order-of-scattering approach, we then compute a numerical Monte Carlo solution for the scattering problem with an exact treatment of the interaction between two volume elements. We compute both the direct and reciprocal contributions along a sequence of volume elements, allowing us to evaluate the coherent backscattering effects. We show that the RT and exact STMM solutions are in mutual agreement for large finite systems of densely packed spherical particles. We conclude that the RT method provides a viable numerical solution for scattering by asymptotically infinite systems of particles.
我们考虑光在由密集堆积的球形颗粒组成的离散随机介质中的散射和吸收。在我们称为“具有相互作用的辐射传输”（RT）中，我们引入随机介质的一个体积元，使用叠加T矩阵方法（STMM）推导其散射和吸收特性，并计算其频域非相干体积元散射特性。然后，我们采用逐次散射方法，对散射问题进行数值蒙特卡罗求解，并精确处理两个体积元之间的相互作用。我们沿着一系列体积元计算直接贡献和互易贡献，从而能够评估相干背散射效应。我们表明，对于密集堆积的球形颗粒的大型有限系统，RT和精确的STMM解相互一致。我们得出结论，RT方法为渐近无限粒子系统的散射提供了一种可行的数值解。
