Light-Induced Abrupt Hydrodynamic Inversion of Molecular Orientation Direction in Liquid Crystals

The problem of laser-induced hydrodynamic reorientation (LIHR) of the director of a hybrid-oriented nematic liquid crystal (NLC) with arbitrary boundary conditions has been numerically solved. LIHR is studied at different laser powers and for two opposite directions of the temperature gradients. The hydrodynamic flow velocity gradient results in a small increase in curvature when light creates a temperature gradient in the out-of-curvature side of the hybrid orientation. The curvature changes sign when light creates a temperature gradient from outside to inside the curvature of the hybrid orientation. The dependence of reorientation on the anchoring energy of molecules to the boundaries is also investigated.