Open AccessSpectral and Spatial Features of Radiation Emitted by a Cholesteric Liquid-Crystal Laser
Author(s) -
I. P. Ilchyshyn,
Е. А. Тихонов,
T. V. Mykytiuk
Publication year - 2018
Publication title -
ukrainian journal of physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.213
H-Index - 17
eISSN - 2071-0194
pISSN - 2071-0186
DOI - 10.15407/ujpe63.4.339
Subject(s) - cholesteric liquid crystal , lasing threshold , materials science , laser , optics , planar , ternary operation , radiation , liquid crystal , photonic crystal , bragg's law , longitudinal mode , reflection (computer programming) , zigzag , optoelectronics , molecular physics , ring laser , physics , diffraction , computer science , programming language , computer graphics (images) , geometry , mathematics
Spectral and spatial characteristics of radiation emitted by a laser operating on the Bragg structure arising in cholesteric liquid crystals (CLCs) have been studied, as well as their variations with a change of the planar CLC orientation. A defect in the helical structure of the CLC formed by a ternary mixture of cholesterol viscous esters is revealed at the mutually orthogonal orientations of the CLC director at the substrates. This defect manifests itself as a local dip in the selective reflection band, which agrees with the behavior of the defect mode in the photonic crystal. Such a defect in the helical structure stimulates the selection of longitudinal modes with the indices N = ±1, so that the single-mode lasing regime is realized. A spatial ring structure in the laser radiation is found to arise, when higher longitudinal modes are generated.