Author:
Rosen-Zvi Michal,Taitelbaum Haim
Abstract
We study frequency-domain spectroscopy for reflectance measurements in two-layered tissues, using a random-walk model of photon migration. We study the phase shift of the reflected light as a function of the source-detector separation, and show that there can be as many as three different types of behavior of this quantity, depending on the relation between the modulated frequency and the absorptivities of both layers. As a result, the possibility of determining the absorptivities of the two layers and the upper layer thickness from the phase shift is different in each regime.