Chen Benyong, Zhang Enzheng, Yan Liping, Liu Yanna
Nanometer Measurement Laboratory, Zhejiang Sci-Tech University, Hangzhou 310018, China.
Rev Sci Instrum. 2014 Oct;85(10):105103. doi: 10.1063/1.4897520.
Correct return of the measuring beam is essential for laser interferometers to carry out measurement. In the actual situation, because the measured object inevitably rotates or laterally moves, not only the measurement accuracy will decrease, or even the measurement will be impossibly performed. To solve this problem, a novel orthogonal return method for linearly polarized beam based on the Faraday effect is presented. The orthogonal return of incident linearly polarized beam is realized by using a Faraday rotator with the rotational angle of 45°. The optical configuration of the method is designed and analyzed in detail. To verify its practicability in polarization interferometry, a laser heterodyne interferometer based on this method was constructed and precision displacement measurement experiments were performed. These results show that the advantage of the method is that the correct return of the incident measuring beam is ensured when large lateral displacement or angular rotation of the measured object occurs and then the implementation of interferometric measurement can be ensured.
测量光束的正确返回对于激光干涉仪进行测量至关重要。在实际情况中，由于被测物体不可避免地会旋转或横向移动，不仅测量精度会降低，甚至可能无法进行测量。为了解决这个问题，提出了一种基于法拉第效应的新型线偏振光束正交返回方法。通过使用旋转角度为45°的法拉第旋转器实现入射线偏振光束的正交返回。详细设计并分析了该方法的光学结构。为了验证其在偏振干涉测量中的实用性，构建了基于该方法的激光外差干涉仪并进行了精密位移测量实验。这些结果表明，该方法的优点是当被测物体发生较大横向位移或角旋转时，能确保入射测量光束的正确返回，进而确保干涉测量的实现。
