Research On Polarization Aberration In Large-aperture Polarization Phase-shifting Interference System

Large-aperture optical components play an important role in cutting-edge technology fields such as astronomy and energy.Their efficient processing is the guarantee for these technologies.The key factor restricting the processing of large-aperture optical components is optical inspection.The polarization synchronization phase-shifting interferometry using the micro-polarization array as the phase shifter has been widely used because of the advantages of non-contact,digital measurement,anti-vibration,etc.However,for large-aperture optical flat crystal detection,it will cause double stress due to its own gravity.Refraction introduces polarization aberration in the measurement result.This paper studies a model correction method for the polarization aberration equivalent wave plate.The main research contents are as follows:Based on the concept of polarized light and the structure of the micro-polarization array,the principle of polarization phase-shifting interferometry is explained using Jones vector and Jones matrix.The analysis focuses on the advantages of large-aperture polarization phaseshifting interferometer,and points out that the disadvantages of the system are mainly caused by the polarization error caused by the imperfection of the polarization element and the polarization aberration caused by the large-aperture flat crystal itself.The clear definition of polarization aberration is explained,and the source of polarization aberration in the large-aperture polarization system: the stress birefringence caused by the gravity of the large-aperture flat crystal is analyzed.In order to eliminate the polarization aberration,an equivalent wave plate was established,and the Jones matrix of the ideal interference light field of the linear and circular polarized light under the wave plate model was briefly derived,which embodied the abstract polarization aberration.The principle of the Lissajous figure and the ellipse fitting method is described,and the influence of the polarization element in the polarization system is corrected.Simulation and experiment verify the effectiveness of the method to eliminate the frequency print through errors.Aiming at the unique polarization aberration problem in the large-aperture system,the relationship between the ideal phase and the actual phase is analyzed through the Jones matrix on the basis of the equivalent wave plate,the parameters of the wave plate model are analyzed,and the specific expression of the polarization aberration is obtained and be corrected.A 600 mm aperture Fizeau interferometer was built,and a polarization light source module was designed.The equivalent wave plate model method was experimentally verified in the case of online polarization.By comparing the experimental data before and after correcting the polarization aberration,and comparing the corrected experimental data with the wavelength phase shift measurement result,the PV value only differs by 0.0066? and the RMS differs by0.0013?,which proves that the equivalent wave plate model corrects the polarization.The feasibility of aberrations.