描述了激光合成波长纳米测量干涉仪的测量原理,分析了非线性误差对该干涉仪的影响,得出了由偏振光非正交、椭偏化和光学元件偏振非正交及椭偏化等对该干涉仪造成的非线性误差为偏振态误差的二阶或高阶小量。进行了激光合成波长纳米测量干涉仪和激光外差干涉仪的对比实验,结果表明激光合成波长纳米测量干涉仪的最大误差为2.1 nm,优于激光外差干涉仪的最大误差7.5 nm,验证了激光合成波长纳米测量干涉仪的优越性。

The principle of laser synthetic-wavelength nanomeasurement interferometer is described. The nonlinear errors which affect on this interferometer are analyzed. Theoretical analysis results show that nonlinear errors caused by nonorthogonal polarization, elliptic polarization of laser source, nonideal polarization beam splitter and corner prism are second or higher order polarization error, the comparable experiment of laser synthetic-wavelength nanomeasurement inteferometer and a heterodyne interferometer was performed. The maximal error of laser synthetic-wavelength nanomeasurement inteferometer is 2.1 nm, while the maximal error of heterodyne interferometer is 7.5 nm.