Holograms are recorded by a 514-nm laser polarized parallel to the molecular director in an azo-dye-doped nematic liquid crystal. For some surface treatments, the recorded holograms persist in the dark. For glass surfaces, exposure to light polarized normal to the molecular director erases the hologram. The hologram also vanishes when the sample is heated across the nematic to isotropic phase transition but reappears when the sample is cooled back to the nematic phase. The dynamics and strength of this effect depend strongly on the surface treatment of the sample cell. © 1992 Optical Society of America.
holography;liquid crystal devices;nematic liquid crystals;solid-state phase transformations;