液晶空间光调制器相位调制特性的快速测量与标定方法  

Fast Measurement and Calibration Method for Phase Modulation Characteristics of Liquid-Crystal Spatial Light Modulator

作　　者：曾婧潇 洪羽剑 卢钧胜 王宇莹 付晓锋 胡晓东[1] Zeng Jingxiao;Hong Yujian;Lu Junsheng;Wang Yuying;Fu Xiaofeng;Hu Xiaodong(School of Precision Instrument and OptoElectronics Engineering,Tianjin University,Tianjin 300072,China;School of Life Sciences,Tiangong University,Tianjin 300387,China)

机构地区：[1]天津大学精密仪器与光电子工程学院,天津300072 [2]天津工业大学生命科学学院,天津300387

出　　处：《光学学报》2023年第3期95-102,共8页Acta Optica Sinica

基　　金：国家自然科学基金(52275540)。

摘　　要：为提高液晶空间光调制器(LCSLM)在波前相位调制中的精度,提出了一种能对LCSLM实现快速标定的数字全息测量方法。该方法仅需在成像面上采集单幅数字全息图像,就能实时测量LCSLM在特定波长下的相位调制特性,系统结构简单,且无需经过复杂的衍射传播计算,测量效率较高。在不改变光路结构的情况下利用TwymanGreen干涉法开展对比实验,进一步验证了数字全息法在测量精度方面的优势。实验结果表明,LCSLM在标准光波波长(633 nm)下的相位调制范围为0~6.185 rad,利用反插值法校正相位响应的非线性特性使得非线性误差降低到2.45%,有效提升了器件的线性驱动精度。最后,针对LCSLM的波长响应特性,建立了相位波长调制修正系数模型,对LCSLM在非标准光波波长(670 nm)下的实际相位调制范围进行了修正,探究了该器件在双波长干涉测量系统中用于相位校正的可行性。Objective As a new type of phase modulator,the liquidcrystal spatial light modulator(LCSLM)has been widely used in adaptive optics,optical communication,optical tweezers,and digital holography.However,the phase modulation characteristics of LCSLMs are different generally,and the accuracy of phase modulation will be affected by their transportation processes and application environments.Therefore,it is essential to measure and calibrate the phase modulation characteristics of an LCSLM before using the device for phase modulation and compensation.Nevertheless,the currently used measurement methods still suffer from limitations.Traditional radial shearing interferometry and TwymanGreen interferometry are usually inefficient and difficult to meet the requirements for rapid detection.Commercial Fizeau interferometers can only measure the phase modulation characteristics of the LCSLM at a fixed light wavelength.In addition,these methods ignore the influence of light wavelength on phase modulation characteristics.In this study,a fast measurement and calibration method based on digital holography is proposed,and the phase modulation characteristics of the LCSLM at different light wavelengths are systematically evaluated.Digital holography exhibits excellent measurement accuracy and efficiency.We expect that our method can be helpful in improving the accuracy of LCSLMs in phase modulation and compensation.Methods Digital holography is used to measure and calibrate an LCSLM in this study.First,an experiment setup of a digital holography system is developed,in which the LCSLM is used as an object.Then,a driving image with gray levels of 0-255 is loaded on the LCSLM,and a digital hologram is recorded on the image plane.The phase distribution of the object wave can be obtained by using the reconstruction algorithm,and the relationship between the phase and the gray level of the LCSLM at the specific wavelength can be determined.Next,without changing the structure of the setup,a comparative experiment is carried out using Twym

关 键 词：测量 液晶空间光调制器 相位调制 数字全息 非线性校正 波长响应 

分 类 号：O438.1[机械工程—光学工程]