Surface-sustained permanent gratings in nematic liquid crystals doped with carbon nanotubes

Response properties of photoinduced gratings were studied in planar cells of liquid crystal doped with multiwalled carbon nanotubes. The grating formation time deduced from beam-coupling measurements was obtained to be ~30 ms. Absorption spectroscopy implies that the permanent gratings are associated with periodically distributed carbonaceous material adsorbed on the inner surfaces of the cell windows under prolonged illumination to the 514.5-nm beams, giving rise to the persistent lightinduced modulation of the easy axis.