Open AccessAll-optical responsive azo-doped liquid crystal laser protection filter
Author(s) -
Ethan I. L. Jull,
Helen F. Gleeson
Publication year - 2018
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.26.034179
Subject(s) - materials science , polarizer , laser , optics , liquid crystal , extinction ratio , liquid crystal tunable filter , optoelectronics , laser power scaling , distributed feedback laser , filter (signal processing) , birefringence , wavelength , physics , computer science , computer vision
An all-optical switchable twisted nematic liquid crystal system has been designed for use as a laser protection filter, which takes advantage of light-induced modification of liquid crystal order. The filter employs photochromic azo-doped liquid crystal mixtures that have been optically characterized and incorporated into a laser filter device. The ability to switch between transmission and blocking modes is shown to occur, even for incredibly low intensity (0.5 mW) irradiation with a continuous 405 nm laser. The blocking-state extinction is defined only by the polarizer extinction ratio, and sub-second switching is demonstrated for these low laser intensities. The response is sufficiently fast to provide protection for CCD cameras against laser damage. The optical switching time is shown to depend on both temperature and laser power. This automatic photo-switchable device offers an exciting approach for passive laser protection.