Oscillations, traveling pulses, and layering in optical bistability and multistability

Detailed theoretical and numerical studies are performed on a bistable distributed semiconductor system showing competing optical nonlinearities, where allowance is made for the transverse diffusion for the kinetic variables determining the optical constants. It is found that diffusion can lead to transverse effects entirely novel for optical bistability, where the dynamic response is much more complicated than switching waves. The effects relate to moving or fixed spatially inhomogeneous structures taking the form of traveling pulses or static layering. These structures can arise either with minor external perturbations or even spontaneously and represent good examples of self-organization characteristics of highly nonequilibrium systems. Present analysis also shows that such systems can show new spatially homogeneous oscillatory states.