纳米精度外差式激光干涉仪非线性误差修正方法研究

A New Method to Correct the Nonlinear Errors in Heterodyne Interferometry

提出一种外差干涉非线性误差修正方法,采用混频技术将光频信号降低到通用数据采集系统频率响应范围内;采用高速数据采集板实现外差干涉测量信号和参考信号双通道同步实时采集;对采集数据进行光滑处理,滤除高阶非线性误差;解出位移量对应的相位差。试验结果表明,所提出的修正方法可以较好地修正双频激光干涉仪中存在的非线性误差,使外差干涉仪测量不确定度由原来的20nm降低到10nm。

A new nonlinear-error correction-method for the heterodyne interferometer was proposed.The data are smoothened to filter the higher order nonlinear errors.The frequencies of both the measurement signals and the reference signals are lowened synchronously within the band of the data acquiring systems using the mixing-frequency technique,and the signals are acquired synchronously through double channels A/D boards,and then the phases to be measured are evaluated.The experimental setup is given.The experimental results illustrate that the proposed nonlinear-error-correction method can reduced the uncertainty in the heterodyne interferometer from 20nm to 10nm.