PARTIALLY POLARIZED LIGHT-INDUCED FREEDERICKSZ TRANSITION IN NEMATIC LIQUID-CRYSTALS

The combination of two noncoherent copropagating beams enables us to s tudy the roles of the electromagnetic field symmetry and angular momen tum in optically induced Freedericksz transition. The particular choic e of the interaction geometry allows one to achieve all-optical contro l of the spatial and dynamic behavior of orientational modes of this t ransition. The collective molecular precession rate is continuously co ntrolled via the light angular momentum transfer. This control is coup led with the change of twist deformation of molecular orientation. Cor responding theoretical model is proposed and analytical solutions are obtained, providing insight into the multitype deformation behavior of the orientational transition and the possibility of its optical contr ol. Excellent quantitative agreement between experimental and theoreti cal results is demonstrated. [S1063-651X(98)10110-1].