Interferometer Testing for Precision Flatness Measurement in Metrology

In short Interferometers measure flatness by comparing a test surface with a very flat reference surface using coherent laser light. Each fringe is half a wavelength of height. In a reflective set-up such as a Fizeau interferometer, one fringe of deviation equals λ/2, about 316 nm at 632.8 nm. The method is non-contact, fast and […]
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