Continuous phase plate (CPP) is the vital diffractive optical element in large laser devices. It is extremely difficult to manufacture owing to its random and small feature structures. Bonnet polishing (BP) has obvious advantage of high efficiency, and has great potential in high-efficient manufacturing of large optics. In the paper, BP techniques have been developed to manufacture CPP. Firstly, the relationship between the process parameters and tool influence functions (TIFs) has been analyzed, and the adjustable ranges of TIF size and efficiency have been determined. Then, a surface topography simulation model for the forecast of CPP residual errors has been established. Based on the model, the influence of TIF size on the accuracy of CPP has been simulated and analysed, meanwhile the optimized TIF has been determined. Finally, an experiment has been carried out by a 300mm×300mm CPP element. The result has shown that the residual root-mean-square (RMS) of CPP is 26 nm. Based on the optimized TIF of BP, it has been realized the high-efficient and high-precision processing of CPP in this paper, and a new technical reference for the CPP manufacturing has been provided simultaneously.
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