Photon path length distribution in random media from spectral speckle intensity correlations

We show that the spectral speckle intensity correlation (SSIC) technique can be profitably exploited to recover the path length distribution of photons scattered in a random turbid medium. We applied SSIC to the study of Teflon slabs of different thicknesses and were able to recover, via the use of the photon diffusion approximation theory, the characteristic transport mean free path ℓ* and absorption length sa of the medium. These results were compared and validated by means of complementary measurements performed on the same samples with standard pulsed laser time of flight techniques. © 2011 EDP Sciences and Springer.