Effect of host medium absorption on polarized radiative transfer in dispersed media.

This paper focuses on polarized radiative transfer in a thin layer composed of titanium dioxide particles while considering the effect of host medium absorption on particle scattering. The single-scattering properties of particles in an absorbing medium are calculated using the modified Lorenz-Mie program recently developed based on the first-principles theory of electromagnetic scattering, and the vector radiative transfer equation is solved by using the spectral element method. The relative errors of Stokes parameters caused by using the conventional Lorenz-Mie theory are systemically investigated. The results show that neglecting the effect of host medium absorption on particle scattering has a more significant impact on the radiation intensity than the polarization components in most cases. Meanwhile, the relative errors of Stokes parameters induced by using the conventional Lorenz-Mie theory obviously increase with the increase of the host medium absorption index and particle size parameter. Due to the larger scattering coefficients and scattering albedos (i.e., for the case of particle size parameter x=10.0 in this study), the relative errors of Stokes parameters of monodisperse particles are obviously larger than those of polydisperse particles. Moreover, it is found that the relative errors of the Stokes parameters change nonlinearly with the particle volume fraction, especially for large size particles.