Liquid crystal gratings based on alternate TN and PA photoalignment

• DOI: 10.1364/oe.20.005384
• Publication Date: 2012-02-21T15:43:03Z
• Authors: Wei Hu; Abhishek Srivastava; Fei Xu; Jia-Tong Sun; Xiao-Wen Lin; Hong-Qing Cui; Vladimir Chigrinov; Yan-Qing Lu
• Keywords: Polarizer; Extinction ratio; Diffraction efficiency; Modulation (music)

A diffraction grating is proposed by periodically defining the liquid-crystal director distribution to form alternate parallel aligned and twist nematic regions in a cell placed between two crossed polarizers. Based on combined phase amplitude modulation, both 1D 2D tunable gratings are demonstrated. Low voltage ON/OFF switching of 1st order diffracted light with extinction ratio over 80 achieved within small interval 0.15 Vrms. Unique four-state feature obtained their applications optical logic devices discussed.