基于双手性液晶超结构的自旋解耦彩色全息  

Spin-decoupled color holography via bi-chiral liquid-crystal superstructures

作　　者：孙睿 刘思嘉 陈鹏 陆延青[1] SUN Rui;LIU Sijia;CHEN Peng;LU Yanqing(College of Engineering and Applied Sciences,Nanjing University,Nanjing 210023,China)

机构地区：[1]南京大学现代工程与应用科学学院,江苏南京210023

出　　处：《液晶与显示》2024年第12期1657-1666,共10页Chinese Journal of Liquid Crystals and Displays

基　　金：国家重点研发计划(No.2021YFA1202000);国家自然科学基金(No.62222507,No.62175101)。

摘　　要：随着人们对信息容量和色彩的要求日益提高,彩色光学全息术备受关注,目前已广泛应用于彩色显示、AR/VR、信息加密等领域。然而,目前的彩色全息术大多基于超表面等体系,在以液晶为代表的软物质中,实现彩色全息仍具有挑战性。本文提出一种上下分层的双手性胆甾相液晶超结构,结合液晶光取向和布拉格反射带调控技术,实现圆偏振复用的彩色全息。其中,利用表面诱导聚合的洗去-重填工艺和液晶光控图案化技术,实现了自旋解耦的几何相位,可对左右旋圆偏振光进行独立的相位调制。入射光只有在偏振、波长均与胆甾相液晶匹配时才能获得几何相位并产生全息图像,通过独立调控左右旋胆甾相液晶的布拉格反射带,在同一衍射面上成功产生了多种全息图像,可调的彩色复用全息得以呈现。本研究提出的基于双手性液晶超结构的自旋解耦彩色全息术有望助力先进显示、光学加密和多通道通信等领域。As the demand for information capacity and color quality continues to increase,color optical holography has garnered significant attention and is now widely applied in areas such as color displays,augmented reality(AR)/virtual reality(VR)and information encryption.However,most current color holography techniques are based on metasurfaces and similar systems,achieving color holography in soft matter,specifically those represented by liquid crystals,remains challenging.In this study,we propose a bi-chiral cholesteric liquid crystal(CLC)superstructure,which enables circular polarization multiplexed color holography through the liquid crystal photoalignment and Bragg reflection band modulation techniques.By employing washout and refill steps involving a surface-initiated polymerization process,alongside liquid crystal photopatterning technology,we achieve spin-decoupled geometric phase,enabling the independent phase modulation of left-and right-handed circularly polarized light.The geometric phase and the resultant holographic image are generated exclusively when the incident light’s polarization and wavelength precisely match those of the CLC.Through the independent control of Bragg reflection bands in left-and right-handed CLCs,multiple holographic images are successfully generated on the same diffraction plane,resulting in the tunable and multiplexed color holography.The proposed spin-decoupled color holography via bi-chiral liquid crystal superstructures holds great promise in advanced displays,optical encryption and multi-channel communication.

关 键 词：彩色全息 液晶 手性超结构 几何相位 光复用 

分 类 号：O436[机械工程—光学工程] O753.2[理学—光学]