Photorefractive-like gratings in non-doped nematic liquid crystal cells induced by photoelectric activation of polymer-liquid crystal interface

The paper is on the experimental evidences of surface induced PR-like diffraction gratings in pure nematic planar cells under the combined application of low intensity optical waves. A model based on photoinduced injection of electronic carriers through the liquid crystal-polymer interface and successive recombination with counter ions accumulated on the opposite side of the interface is discussed. The low light intensity values and the dc voltage applied to observe the effect, demonstrate a very high sensitivity of the liquid crystal devices.