Singular optical reordering of liquid crystals using Gaussian beams
Résumé
We introduce the concept of singular optical reordering of birefringent elastic media using Gaussian beams. Theoretical and experimental results are reported in the particular case of a uniformly aligned nematic liquid crystal film illuminated at normal incidence by a circularly polarized beam. The longitudinal component of the light field is demonstrated to be at the origin of cylindrically symmetric singular reorientation of the optical axis that can be described by the superposition of a radial and azimuthal elastic distortion field. Moreover, the handedness of the overall reorientation pattern is controlled by the handedness of the incident beam circular polarization.