反射式光取向液晶偏振体全息柱透镜的特性  

Characteristics of reflective liquid crystal polarization holographic cylindrical lenses

作　　者：马陈文 陈芳芳 郑继红 MA Chenwen;CHEN Fangfang;ZHENG Jihong(Shanghai Key Laboratory of Modern Optical System,School of Optical-Electrical and Computer Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China)

机构地区：[1]上海理工大学光电信息与计算机工程学院,上海市现代光学系统重点实验室,上海200093

出　　处：《物理学报》2025年第7期243-252,共10页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:62475158)资助的课题。

摘　　要：光取向液晶技术是利用偏振光照射来实现液晶分子的定向排列,该技术可以研制成偏振体全息光栅,具有偏振和体全息选择特性,且作为光耦合元件在光学波导及扩瞳输出方面有广泛应用前景.本文报道了一种采用光控取向技术与偏振离轴全息光路相结合的方法,制备了光斑直径为2 cm的液晶偏振体全息柱透镜.实验过程中可通过控制曝光角度来获得所需光栅周期变化范围,实现红绿蓝RGB三色光入射不同光栅周期下的衍射角角度相同.结果表明,在1721.2—5346.5 nm的光栅周期变化范围内,当RGB三色光分别入射至光栅周期为3147,2649.1,2275.6 nm位置上时,所测得的衍射角度均为11.59°,实际衍射角度与理论衍射角度的误差不超过±0.5°;在532 nm右旋圆偏光下,正入射的衍射效率达90.6%,满足布拉格条件的斜入射衍射效率为84.4%;此外,通过实现光斑的一维扩束,初步验证了PVLS在彩色波导领域应用的可行性.Photo-oriented liquid crystal technology utilizes polarized light illumination to achieve the directional alignment of liquid crystal molecules.This technology can be developed into polarization volume gratings(PVGs),which possess polarization and volume holographic selectivity characteristics,and also have a broad application prospect as an optical coupling element in optical waveguides and for pupil expansion output.This paper reports on the fabrication of a liquid crystal polarization volume holographic cylindrical lens(PVLS)with a beam diameter of 2 cm by using photo-oriented technology combined with a polarization off-axis holographic optical path.During the experiment,the exposure angle can be controlled to achieve the desired grating period variation range,enabling the diffraction angles of red,green,and blue light incident on different grating periods to be the same.The experimental results show that within the grating period variation range from 1721.2 to 5346.5 nm,when the red,the green,and the blue light are incident on grating with periods of 3147 nm,2649.1 nm,and 2275.6 nm respectively,the measured diffraction angles are all 11.59°,with an error between the actual and theoretical diffraction angles within±0.5°;under 532-nm right-handed circularly polarized light,the diffraction efficiency for 18 normal incidence reaches 90.6%,and the diffraction efficiency for oblique incidence satisfying the Bragg condition is 84.4%;simultaneously,beam expansion in one-dimensional direction is achieved,preliminarily verifying the feasibility of PVLS application in the field of color waveguides.

关 键 词：光控取向 液晶 变间距偏振光栅 光波导 

分 类 号：O436[机械工程—光学工程]