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Proceedings Paper

Liquid crystal 3D periodic gratings based on photo-alignment (Conference Presentation)

Paper Abstract

By illuminating a photo-alignment layer with two interfering UV laser beams with opposite circular polarization, a periodic alignment pattern is obtained for nematic liquid crystal. In a liquid crystal cell two substrates are used with periodic photo-alignment, with the periodicities perpendicular to each other. After filling with nematic liquid crystal the director obtains a 3D pattern with period twice that of the photo-alignment. The resulting 3D structure depends on the cell thickness (between 3 and 20 m) and the periodicity of the photo-alignment (also between 3 and 20 m). The director pattern can be estimated by performing numerical simulation with a Q-tensor method. The simulation results can be verified by polarization optical microscopy or by observing the diffraction properties of the structure. For a long range periodicity combined with a small period, the light is efficiently distributed over a small number of diffraction orders. The director pattern can be reoriented by applying a potential difference between the two substrate electrodes. Optical and electrical steering is investigated for devices with different dimensions.

Paper Details

Date Published: 19 September 2017
Proc. SPIE 10361, Liquid Crystals XXI, 1036110 (19 September 2017); doi: 10.1117/12.2275050
Show Author Affiliations
Kristiaan Neyts, Univ. Gent (Belgium)
Inge Nys, Univ. Gent (Belgium)
Varsenik Nersesyan, Univ. Gent (Belgium)
Jeroen Beeckman, Univ. Gent (Belgium)

Published in SPIE Proceedings Vol. 10361:
Liquid Crystals XXI
Iam Choon Khoo, Editor(s)

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