Method and device for sub-aperture polishing and multi-frequency-band combined modification machining

The invention discloses a sub-aperture polishing multi-frequency-band combined modification machining method and device, and belongs to the field of advanced optical manufacturing. The method comprises the following steps: selecting a plurality of target removal functions for processing from a pre-established removal function library according to the processing precision requirement of a to-be-processed element; obtaining power spectral density convergence rates and power spectral density convergence curves of the plurality of target removal functions; determining at least one crossover frequency as a crossover frequency based on the power spectral density convergence curve so as to divide the whole frequency domain into a plurality of frequency bands; and selecting a target removal function with a high power spectral density convergence rate in each frequency band as a processing removal function to carry out shaping processing on the to-be-processed element. According to the method, the problem that the loc