Optical Fréedericksz transition in liquid crystals and transfer of the orbital angular momentum of light

Phys Rev E Stat Nonlin Soft Matter Phys. 2004 Feb;69(2 Pt 1):021702. doi: 10.1103/PhysRevE.69.021702. Epub 2004 Feb 17.

Abstract

Multistability, out-of-polarization-plane reorientation, and persistent oscillations have been observed in the optical Fréedericks transition in a homeotropically aligned nematic film using a normally incident linearly polarized laser beam with elliptical rather than circular cross section. These features could be ascribed to the presence of an additional optical torque connected with a transfer of the orbital angular momentum of light to the liquid crystal film. A model based on Ritz's variational method confirms this picture.