Electrically Tuneable Cholesteric Mirror
作者:
Daniel Krüerke,
Neil Gough,
Gerd Heppke,
SvenT. Lagerwall,
期刊:
Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals
(Taylor Available online 2000)
卷期:
Volume 351,
issue 1
页码: 69-78
ISSN:1058-725X
年代: 2000
DOI:10.1080/10587250008023254
出版商: Taylor & Francis Group
关键词: Liquid crystals;chiral nematic;discotic;calamitic;reflection spectroscopy;electrooptics
数据来源: Taylor
摘要:
Chiral nematic liquid crystals which possess a large negative dielectric anisotropy (Δε < 0), exhibit a larger dielectric constant parallel to the helical axis than perpendicular to it. In a liquid crystal cell with homeotropic boundary conditions, the direction of the helical axis is parallel to the cell surfaces and the sample adopts a pseudo focal conic texture. On the application of a suitable AC field, the director is rotated, such that the helix direction is now perpendicular to the surface and the sample adopts a Grandjean texture. The wavelength of reflected light in this “field On” state is a function of temperature and the magnitude of the applied field. In this paper we show that highly twisted chiral nematic liquid crystals, which possess a large negative dielectric anisotropy are potentially useful as optical modulators and in electrically tuneable mirrors.
点击下载:
PDF (509KB)
返 回