Beam filamentation and its control in high-power semiconductor lasers

We experimentally measure the first-order spatio-temporal characteristics of filamentation and discover effects of the stripe width. We use an analytic theory to explain and reproduce these results through an expression for the filament gain, in which contributions of various mechanisms can clearly be seen. Through this model and computer simulations, we determine the stability boundaries of the material parameters for which the device will not exhibit filamentary tendencies. We then propose a new method of controlling filamentation using below-bandgap semiconductor nonlinearities. With simulations, we determine under what conditions this imposed nonlinearity can counteract the carrier-induced self-focusing inside the active region.