Weak Localization of Photons: Universal Fluctuations and Ensemble Averaging

Abstract

We have carried out an experimental study of weak localization of photons in a rigid, nonabsorbing, disordered medium. Unlike recent results reported for particles in a fluid, we observe large-amplitude fluctuations in the scattering intensity as a function of angle. Ensemble averaging of these sample-specific fluctuations decreases their intensity and uncovers a sharp peak in the backscattering direction. These results emphasize the common origin of weak localization of electrons, as a wave phenomenon, and of photons which are inherently wavelike.