用预抽气真空腔法测量及补偿空气折射率的研究

Measurement and compensation for refractive index of air using a pre-evacuated airtight sealed cavity

空气折射率的补偿效果在高精度激光干涉测量中起着“瓶颈”作用。分析了空气折射率的补偿原理 ,回顾了几种空气折射率的测量方法及特点。在此基础上 ,深入研究了用预抽气真空腔测量与补偿空气折射率的测量原理、方法和装置。该方法保持了干涉法测量空气折射率能充分反映所有导致折射率变化的环境因素的特点 ,避免了测量过程中由于抽气过程给测量带来的干扰。通过空气折射率测量及补偿实验 ,证实了该方法的可行性 ,测量结果经补偿后可使精度提高一个数量级。

The compensation effect for refractive index of air is the 'bottle neck' factor in improving the accuracy of interferometric measurement. The theory of compensation for refractive index of air is analyzed. Several methods for measuring refractive index of air are analyzed and effectiveness of compensation is compared. Based on these results, an interferometric device to measure the refractive index of air without air evacuation in the measuring process is studied. A pre-evacuated airtight sealed chamber with 45° slope is employed. It is testified that the method is effective and the measuring accuracy is improved by the experiments of measuring and compensating for refractive index of air.