Comparison of monte carlo simulations with exact Maxwell solutions for polarized light scattering by multiple absorbing spheres

Abstract

The goal of this study was to investigate the differences between radiative transfer theory and Maxwell theory for simulation of light propagation in a turbid medium. Polarization effects as well as absorbing scatterers with complex index of refraction are taken into account. The simulation volume contained different numbers of scattering and absorbing spheres (radius: 1 μm) and was irradiated from one side with a plane electromagnetic wave (λ 600 nm). The absorption was varied as well as the concentration of the scatterers. The resulting 16 Müller matrix elements were compared for the Monte Carlo method as well as for the Maxwell method for all scattering angles. An increasing absorption of the spheres resulted in larger differences especially for the intensity results (M11 Müller matrix element) between the two solution methods, while increasing scatterer concentrations led generally to larger differences for all Müller matrix elements. That means that the results of radiative transfer theory have to be treated with care for high scatterer concentrations and large absorption. By using the presented method, differences between the two theories can be investigated for arbitrary particle size parameters (spheres) and optical properties of the scatterers.