Numerical simulations of subsurface probing in diffusely scattering media using spatially offset Raman spectroscopy.

We present the first elementary model predicting how Raman intensities vary for a range of experimental variables for spatially offset Raman spectroscopy (SORS), a recently proposed technique for the effective retrieval of Raman spectra of subsurface layers in diffusely scattering media. The model was able to reproduce the key observations made from the first SORS experiments, namely the dependence of Raman signal intensities on the spatial offset between the illumination and collection points and the relative contributions to the overall spectrum from the top layer and sub-layer. The application of the SORS concept to a three-layer system is also discussed. The model also clearly indicates that an annular geometry, rather than a point-collection geometry, which was used in the earlier experiments, would yield much improved data.