Gao Hongtang, Wang Zhongyu, Zou Wei, Liu Yuzhang, Sun Shuanghua
Opt Express. 2021 Jan 18;29(2):1396-1411. doi: 10.1364/OE.413252.
A measurement system based on a simple double-beam interferometry is built to realize the measurement of air refractive index with high accuracy. The basic principle of the system is that, through measuring the change of optical path difference caused by rapid and smooth vacuumization, measurement of refractive index of air is converted to length measurement. Error correction and signal processing are studied to ensure high-accuracy measurement of the refractive index of air. Three applicable methods are used in system. The system based on the methods realize the subdivision and counting of interference fringe by software with three-error correction, error compensation for the end-window plates' thickness change caused by vacuumization, steady realization of high vacuum conditions. To verify the accuracy and reliability of the system, the measurement results are compared with that obtained from the method based on empirical Edlén's formula. Analysis result shows that the expanded measurement uncertainty of the system is U = 5×10, with k = 2. The system can be used to compensate the laser wavelength error caused by the refractive index of air with high accuracy.
构建了一种基于简单双光束干涉测量法的测量系统，以实现高精度的空气折射率测量。该系统的基本原理是，通过测量快速平稳抽真空引起的光程差变化，将空气折射率的测量转换为长度测量。研究了误差校正和信号处理，以确保高精度测量空气折射率。系统采用了三种适用方法。基于这些方法的系统通过软件实现干涉条纹的细分和计数，具有三误差校正、对抽真空引起的端窗板厚度变化进行误差补偿、稳定实现高真空条件。为验证系统的准确性和可靠性，将测量结果与基于经验埃德尔公式的方法所获得的结果进行比较。分析结果表明，该系统的扩展测量不确定度为U = 5×10，k = 2。该系统可用于高精度补偿由空气折射率引起的激光波长误差。
