Fabrication of a large-aperture continuous phase plate in two modes using atmospheric pressure plasma processing

In order to fabricate a large-aperture continuous phase plate(CPP)using atmospheric pressure plasma processing(APPP)with high efficiency and precision,the position dwell mode and velocity mode were proposed and the iterative calculation method was developed for the non-constant removal rate.Two 320 mm×320 mm×2 mm CPPs were fabricated with two processing modes.The experiment results show that the velocity mode is capable of significantly reducing the processing time and shape error.The total processing time is decreased from 13.2 h to 9.3 h,and the surface shape error is decreased from 0.158λto 0.119λ(λ=632.8 nm)(root mean square).