Localization of photons in disordered systems

We discuss weak and strong localization of photons in disordered systems. In particular, we review the recent theoretical and experimental developments relating to the following phenomena: (i) the optical Anderson transition; (ii) weak localization and its effect on the optical diffusion constant; (iii) the coherent backscattered peak; (iv) multiply scattered speckle patterns and their similarity to universal conductance fluctuations; (v) ensemble average and time-scales for different systems (random solids versus random liquids); and (vi) dephasing time-contraction due to multiple scattering.