Weak localisation of photons in a disordered two-dimensional medium

The authors calculate the back-scattered intensity of light from a disordered two-dimensional medium which results from the weak localisation (time-reversed trajectories) of photons. They find that for theta > lambda / xi, the shape of the back-scattered peak is identical to that for a three-dimensional system with the same elastic mean free path, where xi is the two-dimensional optical localisation length. The triangular shape which was found for three dimensions is suppressed because all the solutions of Maxwell's equations for the electric field are localised for any degree of disorder.