双波长干涉显微镜波长的双约束标定  

Wavelength calibration with dual constraints for dual-wavelength interference microscope

作　　者：刘乾[1] 黄小津[1] 李璐璐 张辉 LIU Qian;HUANG Xiao-jin;LI Lu-lu;ZHANG Hui(Institute of Machinery Manufacturing Technology,China Academy of Engineering Physics,Mianyang 621999,China)

机构地区：[1]中国工程物理研究院机械制造工艺研究所,四川绵阳621999

出　　处：《光学精密工程》2021年第4期656-664,共9页Optics and Precision Engineering

基　　金：科学挑战计划项目(No.TZ2018006-0205);中国工程物理研究院院长基金资助项目(No.YZJJLX2017007);中国工程物理研究院超精密加工技术重点实验室基金资助项目(No.ZM18009)。

摘　　要：作为测量的精度来源,双波长干涉显微镜的光波长需要精确标定以溯源至长度基准。本文提出了一种基于两个光波长之间关系、波长与长度基准之间约束的标定方法。理论分析得到了表面重构误差与波长误差之间的关系,认为表面跳变与高度对两个光波长具有足够的约束自由度,并基于理论分析提出了一种双约束的标定方法。该方法通过测量斜平面与标准高度台阶,分别约束了两个光波长之间的比例关系与算术关系,然后通过求解两个约束关系能够确定光波长。仿真结果表明,双约束标定波长的精度可达到0.1 nm。经过本文方法标定的双波长干涉显微镜,测量微沟槽深度的精度可达到0.5 nm。本文标定方法仅需一块标准高度台阶,为干涉显微镜提供了一种简单的高精度波长标定方法,并可以推广应用于双波长数字全息、三波长干涉等技术。The measurement accuracy of a dual-wavelength interference microscope(DWIM)is ensured by the two optical wavelengths,which must be calibrated to be traceable in length. A calibration method was proposed for DWIMs that can determine both the relationships between two wavelengths and between the wavelengths and the length reference. First,the relationship between the reconstructed surface and wavelengths was analyzed theoretically,where the surface jump and height place sufficient constraints on the two wavelengths. Then,based on the analysis,a dual-constraint calibration method was proposed to determine the wavelengths. Together with this method,by measuring a flat and a height standard step,two constraints on the wavelength ratio and arithmetic value were established. With the constraints,the optical wavelengths can be calculated by solving equations. Simulations demonstrate a wavelength calibration accuracy of 0. 1 nm with the proposed method. A DWIM calibrated with the method achieves measurement accuracy up to 0. 5 nm by measuring the depth of a micro-groove. The calibration only needs a height step standard. The proposed method provides an accurate,but simple,calibration for a DWIM and can be applied to dual-wavelength digital holography and three-wavelength interferometry as well.

关 键 词：精密测量 干涉显微镜 双波长干涉 波长标定 

分 类 号：TH742[机械工程—光学工程] O436.1[机械工程—仪器科学与技术]