Absolute air refractive index measurement and tracking based on variable length vacuum cell
Absolute air refractive index measurement and tracking based on variable length vacuum cell
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DOI：
10.1117/1.oe.55.6.064112
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发表时间：
2016-06
影响因子：
1.3
通讯作者：
Xiangzhi Yu;Tie-li Zhang;J. Ellis
中科院分区：
文献类型：
--
作者：
Xiangzhi Yu;Tie-li Zhang;J. Ellis
抽象的。本文提出了一种用四个改进型吴型外差干涉仪组成的变长真空室折射率测量系统。该系统有两种工作模式：(1)移动模式，用于在测量开始时测量绝对空气折射率；(2)静态模式，用于监测与传统位移干涉仪相同带宽的空气折射率波动。该系统在测量过程中不需要充气或抽气，可用于实时折射率补偿。通过与经验方程的对比实验，研究了该系统的可行性和性能。该系统与经验公式的测量误差的标准偏差为2.8ppm/107，接近基于环境传感器精度的折射率参考值的不确定度。相对折射率跟踪只有108的几个部分，带宽为10赫兹，但很容易实现高带宽。
Abstract. A refractometer system using four modified Wu-type heterodyne interferometers with a variable length vacuum cell is presented. The proposed system has two working modes: (1) a moving mode for measuring the absolute air refractive index at the start of a measurement and (2) a static mode for monitoring the air refractive index fluctuation with the same bandwidth as a traditional displacement interferometer. The system requires no gas filling or pumping during the measurement and can be used for real-time refractive index compensation. Comparison experiments with empirical equations are conducted to investigate the feasibility and performance of the proposed system. The standard deviation of the measurement difference between the proposed system and empirical equation is 2.8 parts in 107, which is close to the uncertainty of our refractive index reference based on the accuracy of the environmental sensors. The relative refractive index tracking is a few parts in 108 with a bandwidth of 10 Hz, but high bandwidths are readily achievable.