I will apply it in-vivo, on soft tissue to be specific.

so there will be sort of multiple in-homogeneous layers of tissue.

There is a window of transparancy- from ~1.2 to 2 microns - i which the wavelengths are too long for electronic absoption and too short for bond vibrations. This region is very popular in Optical Coherence Tomography. Attenuation in this region is mostly due to scattering, and is usually describedas photon diffusion. Be careful, however, since in a lot of cases the so-called "diffusion model" employed in random-walk simulation is applicable, but the corrersponding "diffusion approximation", which employs paraboloc equations of diffusion, is not.

ok dr.ramer 

could you send me that python code of the transfer matrix algorithm for a laterally stacked homogeneous layers, please?

all of you thanks for help 

Thank you so much sir