FILAMENTATION AND UNDULATION OF SELF-FOCUSED LASER-BEAMS IN LIQUID-CRYSTALS

We describe an experimental and theoretical study of a low-power, cont inuous-wave laser beam interacting with a nematic liquid crystal. Expe rimental observations show strong self-focusing, the onset of beam und ulation and filamentation. A coupled-field model is presented and redu ced through a separation of scales perturbation argument. This analysi s shows that the light-nematic interaction is very different from conv entional self-focusing in Kerr (nonlinear Schrodinger) media, and it p rovides a new optical setting for the study of the physics of complex nonlinear patterns.