Depth mode characteristics of light propagation in real turbid media and media with two-dimensional scattering

Abstract

A study of the depth mode of light propagation in turbid media with slowly decreasing scattering phase function χ(γ) (when the scattering probability decreases more slowly than γ−4 as the single scattering angle γ is enhanced) is performed outside the framework of the Fokker–Planck approximation. We propose and realize a regular procedure for optimum determination of the parameters of a postulated approximate angular spectrum in the depth mode. The dispersion in the depth mode and the depth damping coefficient are found analytically. The obtained results are in good agreement with the results of numerical calculations and transform, in the limit, into known results of the diffusion approximation. The calculations were also performed in a two-dimensional scattering medium, for which the transport equation written in the quasi-diffusion approximation was recently solved exactly for the particular case of the Henyey–Greenstein phase function. In this case very good coincidence of our approximate results with the exact solution is shown.