BRAGG REFLECTION FROM CHOLESTERIC LIQUID-CRYSTALS
BRAGG REFLECTION FROM CHOLESTERIC LIQUID-CRYSTALS
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DOI：
10.1103/physreve.51.1191
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发表时间：
1995-02-01
影响因子：
2.4
通讯作者：
YANG, DK
中科院分区：
文献类型：
--
作者：
STJOHN, WD;FRITZ, WJ;YANG, DK
本文从实验和理论两个方面讨论了单区和多区胆甾相液晶的光学反射特性。通过在胆甾型液晶中分散低浓度的聚合物，制备了多结构域体系。这导致了(被动的)双稳彩色反射式显示器。在这里，我们讨论了聚合物在改变反射特性方面的作用，涉及它们的光谱和观察特性。从理论上讲，我们提供了著名的Berreman方法的一个应用[J.Opt.SoC。上午好。62,502(1972)]适用于由一组不相关的磁区组成的系统，每个磁区由相同的介电各向异性组成，但具有自己的局部取向。利用这一技术模拟了具有螺旋轴取向分布的胆甾相液晶的反射特性。我们进一步说明了从一个域到另一个域的音调的微小波动是如何显著减少任何干涉条纹的。从这些模拟中，我们将展示如何通过使用聚合物网络来实验地控制螺旋轴的取向分布的程度。
In this paper we discuss the optical reflective properties of single and multidomain cholesteric liquid crystals both experimentally and theoretically. The multidomain system has been prepared by dispersing a low concentration of polymer in a cholesteric liquid crystal. This results in a (passive) bistable colorful reflective display. Here we discuss the role of the polymer in altering the reflective properties in regard to their spectra and viewing characteristics. Theoretically we offer an application of the well known Berreman method [J. Opt. Soc. Am. 62, 502 (1972)] suitable for systems composed of an ensemble of uncorrelated domains, each of which is composed of the same dielectric anisotropy, however with its own local orientation. Using this technique the reflective properties of a cholesteric liquid crystal possessing a distribution in the orientation of the helix axes are simulated. We furthermore illustrate how a small fluctuation in the pitch from one domain to another significantly reduces any interference fringes. From these simulations we will show how experimentally by using a polymer network one may control the extent to which the orientation of the helix axes are distributed.