Testing device and method for dual-wavelength tuning interference marked by Fourier transforming phase shifting

Abstract

The invention discloses a testing device and method for dual-wavelength tuning interference marked by Fourier transforming phase shifting. Tunable lasers with different central wavelengths are adopted by the testing device for serving as light sources to work at the same time, interference phase-shifting is achieved through wavelength tuning, and a detector is adopted for collecting a Moire fringe interference pattern formed after two paths of interference light are superposed. Firstly, the Moire fringe interference pattern collected by the detector is subjected to time-domain Fourier transforming to analyze each frequency component, the marking of phase-shifting step amount is completed, and the phase-shifting step amount under two kinds of wavelengths is guaranteed; secondly, the two tunable lasers serving as the light sources are subjected to phase shifting according to the marked phase-shifting step amount to collect and obtain a phase-shifting Moire fringe interference pattern including synthetic wavelength phase information; finally, the phase-shifting Moire fringe interference pattern is subjected to a dual-wavelength phase-shifting interference algorithm to obtain tested phase information. According to the testing device and method for the dual-wavelength tuning interference marked by the Fourier transforming phase shifting, the surface shape range measured by the interference can be broadened, additional optical paths are not needed in single wavelength phase-shifting marking, and the optical path structure and the interference pattern processing algorithm are simple.

Description

technical field [0001] The invention relates to the field of optical interference testing, in particular to a dual-wavelength tuning interference testing device and method for Fourier transform phase shift calibration. Background technique [0002] Optical interferometry is a high-precision, high-sensitivity metrology test method, which is widely used in the measurement of plane, spherical and aspherical surfaces, the measurement of spherical curvature radius, and the measurement of wavefront transmission quality of various lenses, prisms, and optical systems. measurement of various physical quantities. Phase-shifting interferometry technology plays an important role in high-precision optical detection because of its high precision and high degree of automation. The basic principle of phase-shifting interferometry is to introduce an orderly displacement between two coherent lights of the interferometer, and change the phase difference between the reference light and the tes...

AI Technical Summary

Problems solved by technology

The test device has only one frequency-converted laser but needs to achieve wavelength phase-shifting interference at two central wavelengths, so it is time-consuming

In addition, this method needs to perform spectral low-pass filtering on the superimposed interference light intensity map, and the selection of the filter will reduce the accuracy of the test data, and the processing process is complicated

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