Article

Compensation of misalignment error on testing aspheric surface by subaperture stitching interferometry

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Abstract

For the purpose to decrease the misalignment error from a testing aspheric surface by Subaperture Stitching Interferometry(SSI), a translated error compensation method is proposed to subtract the misalignment error from each phase detum and to stitch multi-subapertures precisely. The basic principle and process of the method are researched, and a compensation mode is established based on the mode search algorithm. The experiment is carried on for an off-axis SiC aspheric mirror with a clear aperture of 230 mm×141 mm, the phase data of the whole aperture are stitched precisely and the figure error is compensated by eliminating the misalignment error. For the comparison and validation, the asphere mirror is also tested by null compensation method, and the relative errors of PV and RMS are 0.57% and 2.74%, respectively.

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