Optical multistability and confined orientational states in nematic liquid crystals: strong excitation regime

We use a two-beam technique to optically generate and control new spatiotemporal deformation modes in nematic liquid crystals (NLCs). A multistability that leads to locked molecular reorientations of a light-NLC system is theoretically predicted for light intensities far above the threshold of molecular reorientation. Such multistability does not exist in a single-beam strong excitation regime. The predicted multistability is observed experimentally. Moreover, it is shown that the discretelike behavior of orientational states is directly related to the twist (nonplanar) deformations. An analysis that takes into account the contribution of such deformations is performed, leading to a proposal of a physical model explaining the observed confined orientational states. (C) 2001 Optical Society of America.