影响激光外差高精度计量的几个关键因素

共光路外差干涉仪具有很高的分辨率,但因为安装、调试误差会产生非线性误差,影响系统的测量精度.所以着重分析了影响激光外差计量精度的4个关键因素,即频率混叠、不同被测金属的相位跳变、被测表面的倾斜及物镜的数值孔径;利用激光外差及矢量分析理论,深入研究了频率混叠误差和相位跳变误差的成因、变化规律,并讨论了提高测量系统精度的有效措施.对正确设计和调试激光外差测试系统、提高测量系统精度具有重要意义.

Factors Affecting the Precision of Heterodyne Interferometer

Non linear errors resulted from mis installation of common path heterodyne interferometer affect the precision of its measurement system. Four factors which can lead to such non linear errors were identified,they are the frequency mixing, the phase jump of different metals to be measured, the tilt of the measured surface and NA of the aperture. Based on heterodyne and vector analysis theories, origins and modes of the frequency mixing error and phase jump error were analyzed. On the above basis, procedures to improve the accuracy of the measurement system were suggested. It was demonstrated that the precision of the laser heterodyne measurement system can be improved to nanometer orders.