Theoretical Computation of the Penetration Depth of Light in Turbid Medium

In this study, we examine the fundamental problem of determining the penetration depth of light in a turbid medium, a topic of considerable relevance in optical physics and biomedical applications. To address this issue, the radiative transfer equation (RTE) is employed as a rigorous theoretical framework for describing photon transport in media characterized by both scattering and absorption. The RTE is solved by incorporating the Henyey-Greenstein (HG) phase function, which provides an accurate representation of the angular scattering distribution of photons within the medium. For the solution procedure, the spherical harmonics-based PN method is adopted due to its proven capability in treating complex scattering behaviors with satisfactory accuracy. The average penetration depth of light is evaluated under various optical parameter configurations to elucidate the influence of scattering characteristics on photon propagation. The computed penetration depths are systematically reported in tabular form, accompanied by a representative figure, corresponding to an approximation order of N = 9. The findings presented herein contribute to a deeper understanding of light–matter interactions in turbid media and provide a useful reference for future theoretical investigations and practical applications in optical transport phenomena.