We focus on the fabrication and study of controllable holographic gratings based on azo-dye-doped and undoped polymer-ball-type polymer-dispersed liquid-crystal films. Experimental results indicate that the next step of photopolymerization of the sample with the illumination of Ar+ laser beams after UV curing causes a latent density grating to be recorded. This grating is formed by a selective secondary photopolymerization. Heating and applying a voltage change the structure of the liquid crystal and induce the appearance of the latent grating. Diffraction efficiencies versus temperature, voltage, and state of polarization are studied for both dye-doped and undoped cells and are found to be quite different. This discrepancy is attributable to the reorientation effect of liquid crystals through their interaction with the photo-induced adsorption of the doped dyes on the surface of polymer balls in the dye-doped cell.
© 2002 Optical Society of America
Andy Ying-Guey Fuh, Chia-Rong Lee, and Ya-Hui Ho, "Thermally and Electrically Switchable Gratings Based on Polymer-Ball-Type Polymer-Dispersed Liquid-Crystal Films," Appl. Opt. 41, 4585-4589 (2002)