Laser action in 2D random media

Summary form only given. Laser action is demonstrated via numerical simulations in a localizing bidimensional highly scattering system with gain. Under certain conditions, the lasing modes are directly related to the localized modes of the system in the absence of gain. These localized modes are selected and play the role of randomly located resonant cavities. When gain is large enough to compensate the loss, laser action occurs like in a distributed feedback laser. To perform these simulations, we use a numerical model, the "wave automaton", introduced to describe time-dependent wave propagation in random media.