Browsing by Author "Lin, Kuo-Ren"

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Electrically switchable liquid crystal Fresnel lens using UV-modified alignment film
(2010-12-06)
Jeng, Shie-Chang
;
Hwang, Shug-June
;
Horng, Jing-Shyang
;
Lin, Kuo-Ren
;
影像與生醫光電研究所
A simple method to make a switchable liquid crystal (LC) Fresnel lens with high diffraction efficiency and a low driving voltage was proposed based on the photo-induced surface modification of the vertical alignment layer. UV illumination alters the pretilt angle of alignment layers, a Fresnel zone-distribution hybrid alignment in the homeotropic LC cell can be straightforwardly achieved through UV exposure, yielding a concentric structure of the Fresnel phase LC lens. A remarkable diffraction efficiency of similar to 31.4%, close to the measured diffraction efficiency of the used Fresnel-zone-plate mask of 32%, was detected using a linearly polarized incident beam. (C)2010 Optical Society of America