1 Answers
The transport length in a strongly diffusing medium is the length over which the direction of propagation of the photon is randomized. It is related to the mean free path l by the relation:
l ∗ = l 1 − g {\displaystyle l^{*}={\frac {l}{1-g}}}
with:g: the asymmetry coefficient. g = ⟨ c o s ⟩ {\displaystyle g=\langle cos\rangle } or averaging of the scattering angle θ over a high number of scattering events.
g can be evaluated with the Mie theory.If g=0, l=l*. A single scattering is already isotropic.If g→1, l*→infinite. A single scattering doesn't deviate the photons. Then the scattering never gets isotropic.