涡旋光位移干涉测量方法与信号处理  

Signal processing method for displacement measurement interferometry using vortex beams

作　　者：夏豪杰[1] 谷容睿 潘成亮[1] 赵会宁[1] XIA Hao-jie;GU Rong-rui;PAN Cheng-liang;ZHAO Hui-ning(School of Instrument Science and Opto-electronics Engineering, Hefei University of Technology, Hefei 230009, China)

机构地区：[1]合肥工业大学仪器科学与光电工程学院,安徽合肥230009

出　　处：《光学精密工程》2020年第9期1905-1912,共8页Optics and Precision Engineering

基　　金：国家自然科学基金面上项目(No.51975179);国家自然科学基金重大研究计划资助项目(No.51427805)。

摘　　要：激光干涉测量技术作为超精密测量的重要手段,为实现亚纳米级测量分辨力,通常对干涉周期信号进行数百倍甚至上千倍的插值细分,引入分辨力有效性问题。本文基于涡旋光束的螺旋相位特性,搭建高精度共轭涡旋光干涉位移测量结构,将被测直线位移量与干涉图案绕中心旋转角度建立线性传感关系。信号采集与处理中基于干涉信号特点,结合高速光电探测器进行干涉图案周期计数与相机进行低速干涉图案图像细分,对干涉图案自身进行空间等角度细分,有效降低后继周期信号的细分倍数并提高测量分辨力可靠性,以保证涡旋光干涉信号实时处理系统的亚纳米量级测量精度。搭建涡旋光束拓扑荷数为4的干涉测量实验测试系统,理论上干涉图案旋转1°对应的被测位移量为0.88 nm,设计基于LabVIEW的信号实时采集和处理系统并进行测量分辨力测试与误差分析,在实验室条件下分辨力优于0.5 nm。Interferometry is an important method to realize high-precision measurements.The key requirement for achieving sub-nanometer resolutions is the interpolation and subdivision of periodic interference signals for hundreds or even thousands of times,through which the problem of resolution effectiveness is introduced.Based on the spiral phase property of the Laguerre-Gauss beam,modified high-precision interferometry was conducted using conjugate vortex beams.The measured linear displacement was linearly converted to the rotation of uniformly arranged petal-like interferograms.Regarding signal processing,to improve the measurement reliability,the multiple of the subsequent signal subdivision is effectively reduced via the subdivision of the spatial angles in interferograms.A high-speed photoelectric detection circuit and low-speed image processing were combined and separately used to count the number of integer cycles and image subdivisions to measure the rotation angle.The experimental test system was constructed using conjugate vortex beams with a topological charge value of 4,and 1°rotation of the interferogram corresponded to a theoretically measured displacement of 0.88 nm.The results of the experiment,which employed a real-time signal acquisition and processing system based on LabVIEW and error analysis,demonstrates that the resolution is better than 0.5 nm under normal laboratory conditions.

关 键 词：光电检测 涡旋光干涉 纳米测量 图像处理 

分 类 号：TH711[机械工程—测试计量技术及仪器] TN249[机械工程—仪器科学与技术]