Invention Application
- Patent Title: Electrically switchable polymer-dispersed liquid crystal materials including switchable optical couplers and reconfigurable optical interconnects
- Patent Title (中): 包括可切换光耦合器和可重新配置的光互连的电可切换聚合物分散液晶材料
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Application No.: US10916430Application Date: 2004-08-12
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Publication No.: US20050007639A1Publication Date: 2005-01-13
- Inventor: Lalgudi Natarajan , Richard Sutherland , Vince Tondiglia , Timothy Bunning , Bob Epling , Donna Brandelik
- Applicant: Lalgudi Natarajan , Richard Sutherland , Vince Tondiglia , Timothy Bunning , Bob Epling , Donna Brandelik
- Main IPC: G02B5/32
- IPC: G02B5/32 ; G02B6/34 ; G02F1/1334 ; G03H1/00 ; C09K19/52 ; G02F1/13 ; G03H1/04

Abstract:
A new photopolymerizable material allows single-step, fast recording of volume holograms with properties that can be electrically controlled. Polymer-dispersed liquid crystals (PDLCs) in accordance with the invention preferably comprise a homogeneous mixture of a nematic liquid crystal and a multifunctional pentaacrylate monomer in combination with photoinitiator, coinitiator and cross-linking agent. Optionally, a surfactant such as octancic acid may also be added. The PDLC material is exposed to coherent light to produce an interference pattern inside the material. Photopolymerization of the new PDLC material produces a hologram of clearly separated liquid crystal domains and cured polymer domains. Volume transmission gratings made with the new PDLC material can be electrically switched between nearly 100% diffraction efficiency and nearly 0% diffraction efficiency. By increasing the frequency of the switching voltage, switching voltages in the range of 50 Vrms can be achieved. The optional use of a surfactant allows low switching voltages at lower frequencies than without a surfactant. In an alternative embodiment, a PDLC material in accordance with the invention can be utilized to form reflection gratings, including switchable reflection gratings. In still further embodiments, a PDLC material in accordance with the invention can be used to form switchable subwavelength gratings. By further processing, static transmission, reflection, and subwavelength PDLC materials can be formed. In addition, PDLC materials in accordance with the present invention can be used to form switchable slanted transmission gratings suitable for switchable optical coupling and reconfigurable optical interconnects.
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