光定域化蓝相软晶格结构的光学应用  

Light-patterned blue phase soft cubic superstructure in optical applications

作　　者：袁丛龙 周康 王骁乾 沈冬[1] 郑致刚[1] YUAN Cong-long;ZHOU Kang;WANG Xiao-qian;SHEN Dong;ZHENG Zhi-gang(Department of Physics,East China University of Technology,Shanghai 200237,Chin)

机构地区：[1]华东理工大学理学院,上海200237

出　　处：《液晶与显示》2018年第7期539-547,共9页Chinese Journal of Liquid Crystals and Displays

基　　金：国家自然科学基金(No.61435008;No.61575063);上海市青年科技启明星计划(No.17QA1401100)~~

摘　　要：实验利用表面光取向技术控制蓝相晶格的有序生长,将光定域化取向与分子自组装相结合。通过对基板表面进行交替的取向/非取向控制,平面内获得周期排列的微结构,使蓝相图形化结构的反射光强度在空间上形成周期性调制,同时设计制备了振幅型衍射器件;通过对基板表面做正交取向方向交替排列的微结构,使蓝相图形化结构的反射光相位在空间上形成周期性调制,设计制备了相位型衍射器件。这两类衍射器件均具有对入射光的波段选择性,即只有当入射光的波长局域在蓝相的反射带时才会呈现衍射效应。蓝相液晶软物质的特性又赋予它在电场下可调谐的波段选择性,即反射带位置随电场的增加发生红移从532nm到610nm,电场撤除则回复到初始状态。同时,借助于光取向材料的光可擦写特性,蓝相晶格的取向微结构能够重复的擦写与重构,从而实现不同衍射器件乃至不同衍射调制方式的转换。Combining light-patterning process with self-assembly trait,we applied photo-alignment technique to control the arrangement of liquid crystal blue phase（BP）cubic superstructure.By means of generating alternate aligned areas and non-aligned areas,the amplitude-modulation diffraction devices can be designed,which derives from the periodic reflection intensity of the patterned BP.By means of generating alternate orthogonal alignment directions,the phase-modulation diffraction devices can be designed,which are owing to the periodic reflected phase from the patterned BP.These two types of diffraction devices exhibit peculiarly wavelength-selectivity,which means that light diffraction occurs selectively to certain wavelength.Based on the soft attribute of BP,these devices can respond to applied electric field leading to a tunable wavelength-selectivity.When the external electric field was applied,the corresponding reflection waveband of BP exhibited a continuous red-shifting from 532 nm to 610 nm.Furthermore,apreferable feature of the devices is photo-induced dynamicalerasability and rewritability due to rewritable characteristic of the photoalignment film,which results in realizing the conversion of different diffractive devices and even diffractive modulation modes.

关 键 词：蓝相液晶 光取向 定域化 超结构 衍射 刺激-响应 

分 类 号：TN141.9[电子电信—物理电子学]