Electrically-controllable prism gratings based on liquid crystal films with a photoconductive layer

• Main Authors: Hong-ren Lin, 林宏仁
• Other Authors: Chia-rong Lee
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/26676979429023876916

碩士 === 國立成功大學 === 光電科學與工程研究所 === 96 === This study investigated electrically-controllable prism gratings based on homogeneously-aligned liquid crystals with a photoconductive layer. An ultraviolet-induced conductivity-gradient electrode-like grating pattern of the polymer layer under a gray-scale grating photomask results in a spatially-periodic gradient magnitude of the effective electric field dropping on LC layer under an applied dc voltage. This causes a prism grating with a spatially-periodic gradient reorientation of LCs. An asymmetric diffraction pattern can be obtained when the probe beam passes through the LC prism grating, and the distribution of the asymmetric diffraction pattern can be tuned with different dc voltage and switched between two orthogonal probe polarizations. Simulation based on a diffraction theory under a LC prism grating model is also developed and compared with the experimental results in this thesis.