ASYMMETRIC RESONANT OPTICAL TORQUE IN AZO-DYE-DOPED LIQUID-CRYSTALS

The photoexcitation of dichroic azo dyes creates a torque that results in a complex rotational motion of the host molecules in liquid crysta l. This phenomenon has asymmetric resonant character. Efficient dynami c holograms are formed on reorientation gratings in the steady-state e xcitation regime. Orientational order modulation and three-dimensional molecular reorientation are detected in the transient regime of excit ation. The complex coupling of photoisomerizing dye with nematic host is the origin of the observed phenomena.