Phase Measurement Algorithm in Wavelength Scanned Fizeau Interferometer
Phase Measurement Algorithm in Wavelength Scanned Fizeau Interferometer
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DOI：
10.1007/s10043-004-0337-3
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发表时间：
2004-10
期刊：
影响因子：
1.2
通讯作者：
R. Hanayama;K. Hibino;S. Warisawa;M. Mitsuishi
中科院分区：
文献类型：
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作者：
R. Hanayama;K. Hibino;S. Warisawa;M. Mitsuishi
波长扫描干涉测量允许同时测量由几个平行表面组成的透明物体的顶面形状和光学厚度变化。来自这些表面的干扰信号可以在频率空间中分离，并通过离散傅里叶分析检测其相位。然而，由于物体的折射率色散和波长扫描的非线性，这些信号频率从检测频率偏移。傅里叶分析对信号频率失谐敏感，且受多波束干扰噪声的影响。传统的误差补偿算法不能应用于由三个以上反射面组成的物体。我们提出了一种新的2N-1采样误差补偿算法，该算法可以检测干扰信号中任意阶谐波频率的相位。该算法抑制了信号频率失谐和多波束干扰噪声的影响，可应用于由三个以上反射面组成的复杂物体的测量。
Wavelength scanned interferometry allows the simultaneous measurement of top surface shape and optical thickness variation of a transparent object consisting of several parallel surfaces. Interference signals from these surfaces can be separated in frequency space, and their phases are detected by discrete Fourier analysis. However, these signal frequencies are shifted from the detection frequency by the refractive index dispersion of the object and a nonlinearity of the wavelength scanning. The Fourier analysis is sensitive to the detuning of the signal frequency and suffers from the multiple-beam interference noise. Conventional error-compensating algorithms cannot be applied to an object consisting of more than three reflecting surfaces. We derive a new 2N-1 sample error-compensating algorithm, which allows the phase detection of any order of harmonic frequency among the interference signals. The new algorithm suppresses the effect of signal frequency detuning as well as the multiple-beam interference noise and can be applied to the measurement of complex objects consisting of more than three reflecting surfaces.