纳米精度双频激光干涉仪非线性误差的确定方法

介绍了确定纳米精度双频激光干涉仪非线性误差的两种方法：纳米比对方法和幅值估算方法，前者通过将双频激光干涉仪和计量院纳米精度F-P干涉仪进行纳米比对确定非线性误差，具有测量结果直接和米定义溯源的优点；后者通过测定偏振干涉仪测量信号的幅值调制度估算非线性误差，具有简单易行、受外界因素干扰小等优点。实验结果表明，对于此干涉仪系统，非线性误差的测量结果小于2．5nm，估算结果为1．4nm，两者在误差允许的范围内一致。

Detcrmining the Residual Nonlinear Error of a Dual-frequency Interferometer for Nanometrology

Two methods for determining the residual nonlinear error of a dual-frequency interferometer are proposed. The first is an estimation method, which can get the nonlinearity error based on the amplitude modulation of the measuring signal when moving the reference mirror of the interferometer continuously. This method has the advantages of easy operating and high resistance to the environment influence. The second is nanometer calibration, which can trace the measurement result to meter definition. In this paper, a dual-frequency interferometer named SJD5 with nanometric capability is introduced.Nanometer calibration between SJD5 and a F-P interferometer of the National Institute of Metrology (NIM ) is also described in detail. The residual nonlinearity of SJD5 is determined as 1. 4 nm by the estimated method and less than 2. 5 nm by nanometer calibration. These two results fit well with each other under consideration of environment influence.