Numerical simulation and experimental study of surface waviness during full aperture rapid planar polishing

Surface waviness (or middle spatial frequency error) is one of the most important specifications of large aperture optical components in high-power laser systems. In this paper, the formation mechanism and the influence factors of the surface waviness of large aperture optical components finished by full aperture rapid planar polishing (RPP) process were researched. Firstly, the theoretical formula of workpiece surface figure has been derivated. Furthermore, a numerical analysis model of the surface waviness has been established using 1-D power spectral density (PSD) as evaluation criterion. At last, the surface material removal and waviness of planar optical components polished by RPP process were calculated and experimental verificated. The simulation and experimental results show that workpiece surface will appear obvious waviness (grid or annular ripples) using grid-grooved polishing plate and fixed-eccentric polishing method. By optimizing the lap groove structure parameters and polishing kinematics parameters, the waviness of the workpiece surface can be significantly reduced.