Large dynamic range curvature sensing for large-aperture active-optics survey telescope

In order to ensure the imaging quality of large-aperture survey telescope under dramatic changes of external environment and realize fast alignment, the wavefront sensing system was required to cover a large dynamic range while maintaining the aberration detection accuracy. First, a set of large dynamic range alignment technology was established based on the light intensity distribution of the single-sided defocus image and curvature sensing. Both analytical formulas and machine learning methods were used to figure out the defocusing and other low-order aberrations. Then, theoretical analysis was made on the resolution accuracy of different types of aberrations. Finally, experimental verification was carried out. The results show that the defocusing detection error (take wavefront RMS variation as the criterion) is less than 5%, while the misalignment detection error is less than 15%, which meets the alignment and adjustment requirements.