Photoinduced gyrotropy of the mesophase of liquid crystals
Zel'dovich B. Ya., Tabiryan N. V.
A nonlinear optical activity is predicted in the mesophase of smectic С liquid crystals and of cholesteric liquid crystals in a cell with only a single orienting surface. In the smectic С crystals the nonlinear optical activity results from a rotation of the С -director by the light, while in the cholesteric crystals it results from a change in the pitch of the helix caused by light which is propagating along the axis of the helix. For cell thicknesses ~ 50 μ m, the magnitude of the nonlinear optical activity is determined by the constant η ~0.1 deg-cm/W and is ten orders of magnitude greater than the typical values of the electronic nonlinear optical activity.