Experimental signatures of Anderson localization of light in three dimensions

Abstract

The observation of Anderson localization of light has long been hindered by the lack of clear-cut experimental signatures. Static transmission measurements for instance would show an exponential decrease of intensity, which cannot be distinguished from absorption. Here we present time-of-flight measurements of single photons in three-dimensional samples. At long times, localization leads to a less than exponential decrease of transmission, which is observed for very turbid samples. While absorption cannot account for such a non-exponential decay, it is still important to determine the absorption length independently. This can be achieved from reducing the index mismatch of the scatterers and performing similar time-of-flight measurements. Such a decrease of the scattering power of the particles also shows that the only sample property leading to non-classical diffusion is indeed the turbidity 1 / kl* as predicted theoretically.