Correlation transfer - Application of radiative transfer solution methods to photon correlation problems

Abstract

A correlation transfer equation is developed for multiple scattering applications, and is solved for the field correlation function that is measured by photon correlation experiments. Radiative transport solution techniques are applied, because there is a formal similarity between the two theories. Small correlation delay time, isotropic scattering and optically thick media approximations are made to compare with experimental results and to derive diffusive wave spectroscopy theory, the currently accepted photon correlation theory for optically dense media. The deposition length problem in diffusive wave theory for the backscattering geometry is investigated in detail. To improve the comparison between theoretical and experimental results, it is concluded that the isotropic scattering assumption must be relaxed. Unlike diffusive wave theory, relaxation of the three aforementioned assumptions is straightforwa rd in the correlation transfer theory by adapting existing radiative transport solution methods and will be the subject of subsequent investigations.