Author Affiliations
Abstract
1 National Laboratory of Solid State Microstructures, Key Laboratory of Intelligent Optical Sensing and Manipulation, Collaborative Innovation Center of Advanced Microstructures, and College of Engineering and Applied Sciences, Nanjing University, Nanjing 210023, China
2 School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing 100191, China
Cascaded holography coupled with the secret-sharing scheme has recently gained considerable attention due to its enhanced information processing and encryption capabilities. Here, we propose a new holographic iterative algorithm and present the implementation of cascaded liquid crystal (LC) holography for optical encryption. Each LC layer acts as the secret key and can generate a distinct holographic image. By cascading two LC elements, a new holographic image is formed. Additionally, we showcase the dynamic optical encryption achieved by electrically switching LCs with combined electric keys. This work may offer promising applications in optical cryptography, all-optical computing, and data storage.
liquid crystals holography optical encryption Chinese Optics Letters
2023, 21(12): 120003
液晶显示领域中的一个重要研究方向是液晶电光性能的改善。近年来,液晶-纳米科学见证了纳米掺杂增强液晶电光性质的范式转变。一方面,纳米颗粒具备特殊的理化性质能有效改善分散基质的性质;此外,纳米掺杂的液晶复合体系制备工艺简单、电光特性卓越,在显示领域占据重要地位。利用液晶与纳米颗粒间的不同相互作用,研究人员设计了一系列具有高稳定性、低成本、可调谐和可持续的电光器件。然而,纳米颗粒的掺杂有可能造成结构缺陷,不利于液晶的稳定。因此,纳米颗粒的选择是影响液晶电光性能的关键。本文概述了液晶-纳米复合体系的电光特性,着重讨论了纳米颗粒与液晶分子间可能存在的相互作用。同时,综述纳米颗粒掺杂液晶的研究现状,根据纳米颗粒类型总结了纳米掺杂对液晶电光性能的影响,并在此基础上,对未来液晶显示技术与纳米技术的结合进行了展望。
液晶 纳米颗粒 电光性能 相互作用 liquid crystals nanoparticles electro-optical performance interactions
1 南京邮电大学 集成电路科学与工程学院,江苏 南京 210023
2 南京邮电大学 射频集成与微组装技术国家地方联合工程实验室,江苏 南京 210023
3 南京邮电大学 电子与光学工程学院,江苏 南京 210023
液晶材料在微波频段具有良好的调制特性,在微波可调谐器件领域具有巨大的应用潜力。本文针对液晶材料微波介电常数的测量需求,提出了一种基于人工局域表面等离激元谐振的传感器。通过设计环形谐振器结构,在sub-6 GHz频段形成局域表面等离激元窄带谐振峰。通过给液晶施加外加电场,能够实现对液晶介电常数的调控。通过谐振频点位置的拟合,能够得到对应的液晶的介电常数大小,从而实现液晶材料在微波频段的介电常数的测量。本文研究了不同液晶层厚度、不同液晶介电常数对人工局域表面等离激元谐振频点的影响。随着液晶层厚度增加或者液晶介电常数的减小,谐振频点f1和f2都逐渐增大。当液晶层厚度大于或等于0.5 mm时,谐振频点f1和f2随介电常数的变化具有良好的线性度,且具有高灵敏度(>400 MHz/Δε),远大于基于目前报道的其他形式介电常数传感器。同时,本传感器结构可以在液晶层上下施加电场,从而实现在不同外加电场作用下液晶材料微波介电常数的测量,在液晶微波特性研究领域具有应用潜力。
液晶 微波介电常数 传感器 人工局域表面等离激元 liquid crystals microwave dielectric constant sensor spoof localized surface plasmon
Author Affiliations
Abstract
The blue phase, which emerges between cholesteric and isotropic phases within a three-dimensional periodical superstructure, is of great significance in display and photonic applications. The crystalline orientation plays an important role in the macroscopic performance of the blue phase, where the single crystal shows higher uniformity over the polydomain and monodomain, resulting in higher Bragg reflection intensity, lower hysteresis, and lower driving voltage. However, currently reported methods of forming a single-crystal blue phase based on thermal controlling or e-beam lithography are quite time-consuming or expensive for large-scale fabrication, especially in the centimeter range, thus hindering the broad practical applications of single-crystal blue-phase-based photonic devices. Herein, a strategy to fabricate a large scale single crystalline blue-phase domain using holography lithography is proposed. Defect-free single-crystal domains both in blue phase I and blue phase II with a desired orientation of over 1 cm2 are fabricated based on a nanopatterned grating with periodic homeotropic and degenerate parallel anchoring, with colors from red and green to blue. This holography lithography-assisted strategy for fabrication of a large-scale single-crystal blue phase provides a time-saving and low-cost method for a defect-free single crystalline structure, leading to broad applications in liquid crystal displays, laser devices, adaptive optics elements, and electro-optical devices.
blue phase single crystal holography lithography liquid crystals Advanced Photonics Nexus
2023, 2(2): 026004
Author Affiliations
Abstract
1 College of Electronic and Optical Engineering & College of Flexible Electronics (Future Technology), Nanjing University of Posts and Telecommunications, Nanjing 210023, China
2 National Laboratory of Solid State Microstructures, Key Laboratory of Intelligent Optical Sensing and Manipulation, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210023, China
Electrically driven structural patterns in liquid crystals (LCs) have attracted considerable attention due to their electro-optical applications. Here, we disclose various appealing reconfigurable LC microstructures in a dual frequency nematic LC (DFNLC) owing to the electroconvection-induced distortion of the LC director, including one-dimensional rolls, chevron pattern, two-dimensional grids, and unstable chaos. These patterns can be switched among each other, and the lattice constants are modulated by tuning the amplitude and frequency of the applied electric field. The electrically switchable self-assembled microstructures and their beam steering capabilities thus provide a feasible way to tune the functions of DFNLC-based optical devices.
dual frequency liquid crystals pattern formation gratings diffractions Chinese Optics Letters
2023, 21(1): 010501