Complex nonlinear optical phenomena in nematic liquid crystals

We show that a nematic liquid crystal acted on by a laser field is an apparently simple physical system that, however, undergoes variety of complex dynamic phenomena. We have studied the dynamics of the NLC-reorientation in a homeotropic NLC-cell in a laser beam. The nature and features of observed phenomena are essentially determined by the geometry of interaction. For normal incidence of the light beam, we have found that the knowledge of the speed of reorientation is needed to fully characterize the transition of the system from the unstable to the stable equilibrium. In the case of oblique incidence of light, the director can start persistent oscillations that become irregular and evolve towards a chaotic dynamics in a particular range of the light intensity.