Coherent random lasing: trapping of light by the disorder

Recent discovery of the coherent lasing from various disordered materials adds a new dimension to the conventional physics of light propagation in multiply scattering media. It suggests that in the situation, when the propagation of light is diffusive on average, the coherent feedback can be provided by the sparse disorder configurations that efficiently trap a photon, and thus, serve as random resonators. This scenario of random resonators has been substantiated experimentally by the ensemble averaging of the power Fourier transforms of the random emission spectra. In this paper the current status of the experiment and theory of coherent random lasing is reviewed.