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Proceedings Paper

Photoinduced extrinsic electrical conduction of nematic liquid crystal
Author(s): O. V. Dedov; V. A. Krivoschekov
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Paper Abstract

During recent years the interest in media with strong nonlinear response is growing. These media allow the user to observe different nonlinear optic effects using small intensities of light. It is well known that liquid crystals are rather promising media for this research. This paper is devoted to the experimental research of the photoinduced conduction of a mixture of a nematic liquid crystal and a dye. Dependence of the conduction on the intensity of light was studied for different concentrations of a dye added to the nematic crystal. Also the problem of the optimum type of a dye for observing the photorefractive nonlinearity using Ar+- ion laser was considered. We made the experiments using the following available laser dyes: rhodamine '6G,' rhodamine 'G,' rhodamine 'C' and two ocsasine-type dyes also. The mixture of the nematic crystal 5CB and a dye was placed in a cell of 100 micrometer width, with the plates filmed with the transparent electrodes of SnO2. The dc voltage on the order of magnitude 1 V was applied to decrease the influence of the cell capacity on the conduction measurements of the samples. We used the light of two wavelengths: lambda1 equals 488 nm, lambda2 equals 514.5 nm. The best dyes for these wavelengths were the rhodamine- type dyes. Taking the other two dyes we observed much smaller effect of influence of the laser radiation on conduction of the samples. Maybe the reason was that the pump wavelength of ocsasine dyes is too far way from the wavelength of the radiation used. So the optimum dye must have the wavelength of the pump near to the wavelength used. Using rhodamine 'C' we obtained the dependencies of the induced conduction on laser light intensity for three different concentrations of the dye.

Paper Details

Date Published: 6 May 1996
PDF: 3 pages
Proc. SPIE 2796, ICONO '95: Fundamentals of Laser-Matter Interaction, (6 May 1996); doi: 10.1117/12.239755
Show Author Affiliations
O. V. Dedov, Technical Univ. Chelyabinsk (Russia)
V. A. Krivoschekov, Technical Univ. Chelyabinsk (Russia)

Published in SPIE Proceedings Vol. 2796:
ICONO '95: Fundamentals of Laser-Matter Interaction
Konstantin N. Drabovich; Nikolai I. Koroteev, Editor(s)

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