Limitations of diffusion approximation in describing femtosecond laser transillumination of highly scattering media of biological significance

Abstract

Ultrafast laser pulses transmitted through highly scattering media have been detected by a streak camera. Experimental data, showing the temporal spread of the ultrafast pulse during the transmission through highly scattering media with various optical discontinuities, have been approximated using the diffusion theory. This analysis explicitly shows how the overall optical parameters of the sample (μa,μs′) are influenced by the presence of the discontinuities and proposes the full width at half-maximum as an experimental index of the transition between ballistic and diffusive photon transport.