DEPTH MODE CHARACTERISTICS OF LIGHT-PROPAGATION IN REAL TURBID MEDIA AND MEDIA WITH 2-DIMENSIONAL SCATTERING

A study of the depth mode of light propagation in turbid media with sl owly decreasing scattering phase function chi(gamma) (when the scatter ing probability decreases more slowly than gamma(-4) as the single sca ttering angle gamma is enhanced) is performed outside the framework of the Fokker-Planck approximation. We propose and realize a regular pro cedure for optimum determination of the parameters of a postulated app roximate angular spectrum in the depth mode. The dispersion in the dep th mode and the depth damping coefficient are found analytically. The obtained results are in good agreement with the results of numerical c alculations and transform, in the limit, into known results of the dif fusion approximation. The calculations were also performed in a two-di mensional scattering medium, for which the transport equation written in the quasi-diffusion approximation was recently solved exactly for t he particular case of the Henyey-Greenstein phase function. In this ca se very good coincidence of our approximate results with the exact sol ution is shown. (C) 1995 Optical Society of America.