Surface-assisted optical storage in a nematic liquid crystal cell via photoinduced charge-density modulation

Abstract This study reports the observation of quasi-permanent recording of holographic gratings in a twisted nematic liquid crystal cell by He–Ne 632.8 nm laser light. The cell is equipped with blocking SiO 2 layers and polyimide insulating/alignment layers and filled with liquid crystalline 6CHBT, doped with an anthraquinone derivative dye. Photogeneration in the bulk of the liquid crystal, photocurrent flow, and loading of the surface with spatially modulated charge density are the major mechanisms which lead to surface electric field induced director reorientation. The novelty of the system described by us is the possibility of ac frequency tuning of the intensity of light diffracted at the so formed refractive index grating.