Research On Dual-wavelength M-Z Inteferometer Based On Total Reflection Prism Structure

Phase-shifting interferometry technology has many advantages such as its non-contact,high sensitivity and good repeatability.It has been widely used in optical measurement and detection.The dual-wavelength phase-shifting interferometry technology combines the dual-wavelength holography technology and phase-shifting interference technology to solve the 2π problem that occurs when a traditional single-wavelength measurement of large deviation surfaces is performed on the basis of ensuring high measurement accuracy.The range of the interferometric measurement is also enlarged,so this method has a broader application prospect in the field of optical interferometry.Based on a systematic study of the fundamental theory of dual-wavelength phase-shift interference,this paper designs an MZ dual-wavelength interference system based on the total reflection prism structure that is not easy to be deformed and is easy to adjust.The relevant hardware parameters are determined by calculation and analysis,and the adjustment of the dual-wavelength phase-shift interference system is completed.The wavelengths are 632.8 nm and 532 nm,respectively,and the aperture is 30 mm.Further,the equivalent wavelength phase extraction algorithm is studied.The traditional dual-wavelength algorithm is improved by using ellipse fitting method.A phase extraction dual-wavelength algorithm based on four-step phase shift ellipse fitting is proposed.This method not only expands the depth measurement.The range,in turn,improves the measurement accuracy of the measurement method.Finally,a dual-wavelength phase-shifting interference experimental system was constructed.Using the experimental system,the surface structure of a transparent concave component was measured.The improved dual-wavelength algorithm was used to recover the surface shape information.The obtained equation determined the coefficient R-square as 0.9904;The obtained contour measurement result is compared with the actual sample result,and a consistent conclusion is obtained.It shows that the designed dual-wavelength phase shift interference system is practical in measuring the surface area,and provides reference and reference for the optical detection of transparent elements.