Author Affiliations
Abstract
1 Department of Physics, East China University of Science and Technology, Shanghai 200237, China
2 School of Optoelectronic Science and Engineering & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006, China
3 Advanced Materials and Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, Ohio 44242, USA
The dynamic manipulation of the helicity in a cholesteric helical superstructure could enable precise control over its physical and chemical properties, thus opening numerous possibilities for exploring multifunctional devices. When cholesteric material satisfies the sufficiently small bending elastic effect, an electrically induced deformation named the cholesteric heliconical superstructure is formed. Through theoretical and numerical analysis, we systematically studied the tunable helicity of the heliconical superstructure, including the evolution of the corresponding oblique angle and pitch length. To further confirm the optical properties, Berreman’s 4 × 4 matrix method was employed to numerically analyze the corresponding structure reflection under the dual stimuli of chirality and electric field.
cholesteric liquid crystal heliconical superstructure tunable reflection band electro-optical materials Chinese Optics Letters
2020, 18(8): 080005
1 国网河南省电力公司 信息通信公司, 河南 郑州 450052
2 中国科学院 长春光学精密机械与物理研究所 应用光学国家重点实验室, 吉林 长春 130033
为了提高聚合物/液晶(HPDLC)光栅的衍射效率并改善光栅的表面形貌, 研究了表面垂直取向处理对HPDLC光栅的影响。首先, 研究了表面垂直处理对液晶分子的取向作用, 发现垂直取向层对液晶的锚定作用随着盒厚的增加而逐渐减弱, 取向层的作用范围大概在3 μm ~5 μm之间; 其次, 对相分离程度进行了实验表征, 结果表明, 随着液晶盒厚度的增加, 相分离开始的时间越来越快, 并且分离程度也越来越彻底。最后, 讨论了表面垂直取向对HPDLC光栅衍射效率的影响, 随着盒厚的增加, 相分离出来的液晶微滴形成连续的区域, 光栅的衍射效率逐渐升高, 当盒厚增加到一定程度, 其衍射效率和无取向处理的光栅接近。当盒厚过大时, 垂直取向处理对HPDLC光栅散射损失并没有太大的改善, 只有当盒厚适中(12 μm)时, 光栅的衍射效率最高, 散射损失最小。
表面垂直取向 衍射效率 散射损失 surface vertical alignment HPDLC HPDLC diffraction efficiency scattering loss
