Yin Kun, Xiong Jianghao, He Ziqian, Wu Shin-Tson
College of Optics and Photonics University of Central Florida, Orlando, Florida 32816, United States.
ACS Omega. 2020 Dec 3;5(49):31485-31489. doi: 10.1021/acsomega.0c05087. eCollection 2020 Dec 15.
Liquid-crystal (LC)-based ultrathin flat optical elements (FOEs) exhibit several attractive properties, such as a high degree of optical tunability, strong polarization selectivity, nearly 100% diffraction efficiency, and a simple fabrication process. Investigating the alignment patterning of LC-FOEs to diversify their performance has attracted broad interest in the optics field. In this mini-review, we start from the photoalignment (PA) process and then dive into device structures and performances. By generating and recording the desired polarization fields on the PA layer, the LC molecules will follow the recorded patterns and establish the phase profiles for different functionalities, such as gratings and lenses. Because of the polarization dependency, LC-FOEs have found useful applications in near-eye displays. Understanding the interactions between the PA mechanism and LC molecules helps to optimize the device performance for novel optical systems.
基于液晶（LC）的超薄平面光学元件（FOE）具有多种吸引人的特性，如高度的光学可调性、强偏振选择性、近100%的衍射效率以及简单的制造工艺。研究LC-FOE的取向图案以使其性能多样化已在光学领域引起广泛关注。在本综述中，我们从光取向（PA）过程开始，然后深入探讨器件结构和性能。通过在PA层上生成并记录所需的偏振场，LC分子将遵循记录的图案并建立用于不同功能（如光栅和透镜）的相位分布。由于偏振依赖性，LC-FOE已在近眼显示器中得到了有用的应用。理解PA机制与LC分子之间的相互作用有助于优化新型光学系统的器件性能。
