Simulation of stress deformation in 600mm flat mirror measurement with interferometer

In the process of measuring the Fizeau interferometer, the measured plane mirror is inevitably affected by gravity, which leads to the general situation that the actual plane shape is inconsistent with the measured result. The study shows that the effect of gravity on surface deformation is negligible for small apertures (about less than 100mm), but it is especially obvious for the precision measurement of large-aperture (more than 300mm). In order to reduce the influence of gravity deformation on the measurement results, this paper simulates a variety of fixing schemes for 600mm plane mirrors, selects a better large-aperture plane mirror fixing scheme finally, and obtains the simulation results of 600mm plane mirror surface displacement PV value is 10.79nm, which is less than 1/50λ (λ=632.8nm). It provides a theoretical basis for follow-up experiments.