Probing the dynamics of Anderson localization through spatial mapping

We study (1+1)D transverse localization of electromagnetic radiation at microwave frequencies directly by two-dimensional spatial scans. Since the longitudinal direction can be mapped onto time, our experiments provide unique snapshots of the build-up of localized waves. The evolution of the wave functions is compared with numerical calculations. Dissipation is shown to have no effect on the occurrence of transverse localization. Oscillations of the wave functions are observed in space and explained in terms of a beating between the eigenstates.