Cui Xiaowen, Wu Ming, Dong Han, Qin Xiaobo, Yang Fugui, Zhang Xiaowei, Li Ming, Sheng Weifan
Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Rev Sci Instrum. 2024 Oct 1;95(10). doi: 10.1063/5.0230952.
Compensating for the pitch error in the scanning movement is a fundamental issue when conducting large-scale surface shape measurements with deflectometric profilers. This paper presents a new long trace profiler employing a shearing measurement technique. In this setup, the optical head and the mirror under test are mounted on two independent parallel movable air-bearing carriages to enable shearing and scanning movements separately. The distance between the optical head and the tested mirror remains fixed, effectively minimizing the influence of system errors resulting from imperfections in optical devices. Simulation studies show that the double shear measurement method with a low-spatial-frequency filtering process can effectively mitigate high-frequency angular measurement errors introduced by the instability of the air-bearing stage. Experimental tests conducted on flat mirrors demonstrated a precision of less than 50 nrad rms, thereby confirming the robustness of the system.
在使用偏转轮廓仪进行大规模表面形状测量时，补偿扫描运动中的俯仰误差是一个基本问题。本文介绍了一种采用剪切测量技术的新型长跟踪轮廓仪。在这种设置中，光学头和被测反射镜安装在两个独立的平行可移动空气轴承滑架上，以便分别进行剪切和扫描运动。光学头与被测反射镜之间的距离保持固定，有效地减少了由光学器件缺陷导致的系统误差的影响。仿真研究表明，采用低空间频率滤波处理的双剪切测量方法可以有效减轻空气轴承平台不稳定性引入的高频角度测量误差。在平面镜上进行的实验测试表明，均方根误差精度小于50纳弧度，从而证实了该系统的稳健性。
