Diffusion of light in turbid material

TLDR

Light diffusion in turbid materials such as tissues is described by mathematical techniques including transport theory and radiance models. The paper examines the usefulness and limitations of these techniques. The authors review transport theory, radiance, fluence rate, phase functions, boundary conditions, measurement methods, first‑order solutions, multiple scattering, diffusion approximation, and various wave excitations, including surface scattering from rough interfaces.

Abstract

This paper discusses some of the present knowledge of the mathematical techniques used to describe light diffusion in turbid material such as tissues. Attention will be paid to the usefulness and limitations of various techniques. First, we review the transport theory, radiance, radiant energy fluence rate, phase functions, boundary conditions, and measurement techniques. We then discuss the first-order solution, multiple scattering, diffusion approximation, and their limitations. The plane wave, spherical wave, beam wave, and pulse wave excitations are discussed followed by a brief review of the surface scattering effects due to rough interfaces.