Photorefractivity in polymer-stabilized nematic liquid crystals
Photorefractivity in polymer-stabilized nematic liquid crystals
复制标题
聚合物稳定向列液晶的光折变
DOI：
10.1117/12.328153
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
M. Wasielewski
中科院分区：
文献类型：
--
作者：
G. Wiederrecht;M. Wasielewski
聚合物稳定的液晶，由低浓度的聚合物电子受体，显示出显着增强的光折变性能。这些复合系统的电荷产生和传输特性强烈修改从掺杂电子给体和受体的双相液晶。这种新的复合材料是通过聚合少量的1，4：5，8-萘二酰亚胺电子受体而制备的，该电子受体在取向的双折射液晶中被丙烯酸酯基团官能化。光聚合产生各向异性凝胶状介质，其中液晶在空间电荷场的存在下自由地重新取向，同时在材料的聚合区域中保持电荷捕获位点。这些捕获位点的存在导致在聚合物稳定的液晶中观察到比在单独的液晶中观察到的更长寿命、更高分辨率的全息光栅。这些光栅显示布拉格区衍射。非对称光束耦合，光电导，和四波混频实验进行这些新材料的光物理特性。
Polymer-stabilized liquid crystals, consisting of low concentrations of a polymeric electron acceptor, are shown to exhibit significantly enhanced photorefractive properties. The charge generation and transport properties of these composite systems are strongly modified from nematic liquid crystals doped with electron donors and acceptors. The new composites are produced by polymerizing a small quantity of a 1,4:5,8-naphthalenediimide electron acceptor functionalized with an acrylate group in an aligned nematic liquid crystal. Photopolymerization creates an anisotropic gel-like medium in which the liquid crystal is free to reorient in the presence of a space charge field, while maintaining charge trapping sites in the polymerized regions of the material. The presence of these trapping sites results in the observation of longer lived, higher resolution holographic gratings in the polymer-stabilized liquid crystals than observed in nematic liquid crystals alone. These gratings display Bragg regime diffraction. Asymmetric beam coupling, photo-conductivity, and four-wave mixing experiments are performed to characterize the photophysics of these novel materials.