T-matrix approach and the angular momentum theory in light-scattering problems by ensembles of arbitrarily shaped particles

Abstract

Light scattering by a macroscopically anisotropic volume element, which consists of arbitrarily shaped particles with an arbitrary square-integrable probability-density function over orientations, is considered. The T-matrix approach and the quantum theory of angular momentum are used to develop a rigorous analytical method (in terms of the T matrix) for computing the extinction matrix; the extinction, scattering, and absorption cross sections; and the elements of the Mueller matrix of the volume element. The constructive theorem of the existence of the expansion of scattering-matrix elements in a series of Wigner functions for a medium with rotation symmetry is proved. The analytical results are generalized for incident radiation composed of incoherent plane waves with a square-integrable probability-density function over directions of propagation, intensities, and polarization states.