Luo Songjie, Sasaki Osami, Chen Ziyang, Pu Jixiong
Appl Opt. 2017 May 20;56(15):4419-4425. doi: 10.1364/AO.56.004419.
Complex-valued interference signals (CVISs) of a white-light scanning interferometer (WLSI) and a spectrally resolved interferometer (SRI) are obtained from their real-valued interference signals through Fourier transform. First the phase distribution in the CVIS of the SRI indicates a dispersion phase caused by two sides of unequal length in a cubic beam splitter, and the magnitude of the dispersion phase changes linearly along a horizontal direction of the beam splitter. Next the dispersion phase with a different magnitude is subtracted from the spectral phase in Fourier transform of the CVIS of the WLSI. Through inverse Fourier transform of this spectral distribution, a dispersion-free CVIS is obtained, and the position of zero phase nearest to the position of amplitude maximum provides a surface profile measured accurately with an error less than 4 nm after 2π corrections, while a position calculated by the linear component of the spectral phase causes measurement error less than 12 nm.
通过傅里叶变换从白光扫描干涉仪（WLSI）和光谱分辨干涉仪（SRI）的实值干涉信号中获得复值干涉信号（CVIS）。首先，SRI的CVIS中的相位分布表明了由立方分束器中不等长的两侧引起的色散相位，并且色散相位的大小沿分束器的水平方向线性变化。接下来，从WLSI的CVIS的傅里叶变换中的光谱相位中减去具有不同大小的色散相位。通过对该光谱分布进行傅里叶逆变换，获得了无色散的CVIS，并且最接近幅度最大值位置的零相位位置提供了经过2π校正后误差小于4nm的精确测量的表面轮廓，而由光谱相位的线性分量计算出的位置导致测量误差小于12nm。
