title: Photo-switchable bistable twisted nematic liquid crystal optical switch.
abstract: This work demonstrates a photo-switchable bistable optical switch that is based on an azo-chiral doped liquid crystal (ACDLC). The photo-induced isomerization of the azo-chiral dopant can change the chirality of twisted nematic liquid crystal and the gap/pitch ratio of an ACDLC device, enabling switching between 0° and 180° twist states in a homogeneous aligned cell. The bistable 180° and 0° twist states of the azo-chiral doped liquid crystal between crossed polarizers correspond to the ON and OFF states of a light shutter, respectively, and they can be maintained stably for tens of hours. Rapid switching between 180° and 0° twist states can be carried out using 408 and 532 nm addressing light. Such a photo-controllable optical switch requires no specific asymmetric alignment layer or precise control of the cell gap/pitch ratio, so it is easily fabricated and has the potential for use in optical systems.
authors.affiliation: Department of Photonics, National Sun Yat Sen University, Kaohsiung, Taiwan.
authors.forename: Chun-Ta
authors.initials: CT
authors.lastname: Wang
authors.forename: Yueh-Chi
authors.initials: YC
authors.lastname: Wu
authors.forename: Tsung-Hsien
authors.initials: TH
authors.lastname: Lin
mesh_terms: D004574:Electromagnetic Fields; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008027:Light; D050866:Liquid Crystals / Q000737:chemistry* / Q000528:radiation effects; D012031:Refractometry / Q000295:instrumentation*; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*