title: Thermally and electrically switchable gratings based on polymer-ball-type polymer-dispersed liquid-crystal films.
abstract: 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.
authors.affiliation: Department of Physics, National Cheng Kung University, Tainan, Taiwan. andyfuh@mail.ncku.edu.tw
authors.forename: Andy Ying-Guey
authors.initials: AY
authors.lastname: Fuh
authors.forename: Chia-Rong
authors.initials: CR
authors.lastname: Lee
authors.forename: Ya-Hui
authors.initials: YH
authors.lastname: Ho