Transient effects in cw laser induced reorientation of nematic liquid crystals

Optical diffraction effects in liquid crystals can be large due to the material anisotropy. We report here the observation of reorientational optical nonlinearity for both Raman-Nath and self-diffraction, comparing these with the predictions of a simplified theory. Enhanced transient gratings are demonstrated under continuous wave illumination, which exist because of the material viscosity.