title: Liquid crystal gratings based on alternate TN and PA photoalignment.
abstract: 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 the combined phase and amplitude modulation, both 1D and 2D tunable gratings are demonstrated. Low voltage ON/OFF switching of 1st order diffracted light with extinction ratio over 80 is achieved within a small voltage interval of 0.15 Vrms. Unique four-state feature of the cell is obtained and their applications in optical logic devices are discussed.
authors.affiliation: College of Engineering and Applied Sciences and National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Hu
authors.forename: Abhishek
authors.initials: A
authors.lastname: Srivastava
authors.forename: Fei
authors.initials: F
authors.lastname: Xu
authors.forename: Jia-Tong
authors.initials: JT
authors.lastname: Sun
authors.forename: Xiao-Wen
authors.initials: XW
authors.lastname: Lin
authors.forename: Hong-Qing
authors.initials: HQ
authors.lastname: Cui
authors.forename: Vladimir
authors.initials: V
authors.lastname: Chigrinov
authors.forename: Yan-Qing
authors.initials: YQ
authors.lastname: Lu
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D050866:Liquid Crystals / Q000737:chemistry*; D012031:Refractometry / Q000295:instrumentation*; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*