Fast Surface Profiling by Multi-Wavelength Single-Shot Interferometry

We have developed a fast and robust surface profiling method by using multi-wavelength single-shot interferometry. The interference patterns are simultaneously captured by a newly developed multi-wavelength imaging system, which is easily and economically constructed by using a commercially available RGB LED illuminator and a color camera. With this imaging system, we first developed a two-wavelength single-shot technique and successfully measured 350 nm step height. Then we expanded it to a three-wavelength and successfully measured 1000 nm step height. For this purpose, we have developed some algorithms including crosstalk compensation and frequency estimation. The algorithms used and experimental results are presented.

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