Self-organised formation of an edge-dislocation array and optical vortex generation by reentrant-type nematic liquid crystal.

Authors

Jun Yoshioka, Tasuku Sakikawa, Eiichi Oishi, Shinji Bono, Akitoshi Koreeda, Satoshi Konishi, Koji Fukao

Published in

Soft matter. Oct 06, 2026. Epub Oct 06, 2026.

Abstract

Fork-shaped diffraction gratings generate optical vortices, i.e., light fields with helical wavefronts. To fabricate such a grating, we focus here on the periodic deformation induced near the phase transition between the nematic and smectic A liquid-crystalline phases. Although the periodic structure typically appears over a temperature range of only ∼0.1 K, which is too narrow for practical use as a grating, we show that this range can be extended to several kelvins by using a reentrant-type nematic liquid crystal. Moreover, by introducing a sandwich cell with a step in the substrate, we successfully create edge dislocations in the periodic pattern owing to the mismatch in its period across the step. Upon illuminating a dislocation with laser light, optical vortices are observed in the first-order diffracted beams, whose intensity distributions strongly depend on the incident polarisation. The resulting dislocations thus function as polarisation-sensitive fork-shaped gratings.

PMID:
42834859
Bibliographic data and abstract were imported from PubMed on 06 Oct 2026.

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