【摘要】 双频激光外差干涉法与扫描探针相结合的超精表面缺陷检测系统具有很高的分辨率。但系统光源和光学器件的各种误差因素会产生非线性混频误差,影响系统精确测量。利用琼斯矩阵分析了同时存在激光光源椭圆偏振化和方位角误差以及光学器件相位延迟和偏振泄漏等综合因素引起的偏振态变化,并由此研究了它们频率混叠产生的非线性误差。结果表明,由各种误差因素引起的非线性混频误差呈正弦规律变化,激光光源非理想和偏振分光镜对位移测量误差影响较大而1/4波片的影响较小。同时,结合计算结果对系统提出了减少非线性误差的方法措施。更多还原

【Abstract】 A novel method with high resolution has been proposed which is based on heterodyne interferometry and scanning probe to get the measurement values of superfinish surface scratch. But the optical nonlinear errors affect the measurement precision of the system. We adopt the Jones matrix to analyze the change of elliptic polarization caused by the composite error factors, which are polarization ellipticity and installation orientation error of laser source, phase retardation of quarter- wave plate and polarization leakage of polarization beam splitter. The measurement errors of frequency mixing about these elliptic polarization beams arriving at the photodiode detector are studied by vector theory. The results show that the measurement errors are periodic errors, and they are more affected by nonideal laser and polarization beam splitter. Also, the methods of reducing nonlinear error according to the numerical results in the system are suggested.更多还原