Xu Zhiguang, Shilpiekandula Vijay, Youcef-toumi Kamal, Yoon Soon Fatt
Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
Opt Express. 2009 Aug 17;17(17):15104-17. doi: 10.1364/oe.17.015104.
A special configuration of white-light scanning interferometer is described for measuring the absolute air gap thickness between two planar plates brought into close proximity. The measured gap is not located in any interference arm of the interferometer, but acts as an amplitude-and-phase modulator of the light source. Compared with the common white-light interferometer our approach avoids the influence of the chromatic dispersion of the planar plates on the gap thickness quantification. It covers a large measurement range of from approximate contact to tens of microns with a high resolution of 0.1 nm. Detailed analytical models are presented and signal-processing algorithms based on convolution and correlation techniques are developed. Practical measurements are carried out and the experimental results match well with the analysis and simulation. Short-time and long-time repeatabilities are both tested to prove the high performance of our method.
描述了一种用于测量紧密靠近的两个平板之间绝对气隙厚度的白光扫描干涉仪的特殊配置。所测量的气隙不在干涉仪的任何干涉臂中，而是充当光源的幅度和相位调制器。与普通白光干涉仪相比，我们的方法避免了平板色散对气隙厚度量化的影响。它覆盖了从近似接触到几十微米的大测量范围，分辨率高达0.1 nm。给出了详细的分析模型，并开发了基于卷积和相关技术的信号处理算法。进行了实际测量，实验结果与分析和模拟结果吻合良好。测试了短期和长期重复性，以证明我们方法的高性能。
