Director sliding induced by a circularly polarised light in dye-doped liquid crystals

We report the first detailed experimental study of the transient effects of a circularly polarised beam on dye-doped liquid crystal cells. Experiments show that, as linearly polarized light does, light with circular polarization induces quasi-free sliding of the molecular director on the irradiated surface. The behaviour of the sliding angle vs. the incident intensity, its dependence on the exposure time and its independence on the sign of the light ellipticity, suggest that the phenomenon is connected to surface effects instead of being directly due to the transfer of intrinsic angular momentum from light to the LC molecules.