Position-Dependent Diffusion of Light in Disordered Waveguides

Diffusion is a statistical description of random walk of a classical particle, and the diffusion constant D0 is the only parameter in the diffusion equation. For light as well as for other kinds of waves, this is an approximation, because the interference of partial waves is ignored [1]. Such interference is essential to Anderson localization. Proper account of the interference effects in random samples of finite size [2] and/or with absorption [3] results in spatial variation of the diffusion coefficient D(r) in the self consistent theory (SCT) of localization