Wavelength-switchable Fizeau interferometry and its applications

The wavefront of coated optics is one of critical performances. Due to the interference between the coating layers, the measurement results will be totally different if the measurement wavelength is different from the working wavelength. However, all of the commercial interferometers have single measurement wavelength, which can't treat the optical coatings working at various wavelengths. A wavelength-switchable interferometer (WSI) capable of detecting wavefront information in a wide wavelength range of 488-1064 nm is proposed in this paper. The principle of design and performance of the system are given in detail. Some typical measurement applications, such as reflection plate and optical filters will also be presented.