Diffuse light transmission profiles obtained using CW: A comparative analysis with time resolved experiments

In this work, we investigate the CW transmitted light profiles when an inhomogeneity is immersed in highly scattering media slabs. These profiles show an interesting effect whenever the absorption coefficient, μa, of the inclusion happens to be higher than that of the bulk whereas its reduced scattering coefficient, μs′, is lower than that of the surrounding medium. For this combination of optical properties, the transmitted light displays a peak of higher intensity at scan positions where the inclusion is located, producing a distinctive “W” profile. We have investigated this effect by analyzing the temporal windows of the distribution of times of flight at each scan position. In this way we found that the origin of the “W” profile is due to the contribution of the late photons. Experiments are compared with a theoretical model and with Monte Carlo simulations showing good agreement.