Fig. 1. Schematic diagram of large field freeform optical system

Fig. 2. MTF curves of freeform imaging system

Fig. 3. Spot diagrams of freeform optical system

Fig. 4. Optical and mechanical design

Fig. 5. Optical and mechanical structure of freeform imaging system

Fig. 6. Processing of aluminum alloy freeform optical elements

Fig. 7. Integrated ultra-precision turning of primary and tertiary mirrors

Fig. 8. Mesh projection of freeform equivalent plane removal functions

Fig. 9. Magnetorheological polishing of primary mirror

Fig. 10. Principle for synchronous detection of shape and position accuracy of optical complex surfaces based on CGH

Fig. 11. Synchronous detection of shape and position errors for primary and tertiary mirrors

Fig. 12. Surface errors of primary mirror

Fig. 13. Surface errors of tertiary mirror

Fig. 14. Surface errors of secondary mirror

Fig. 15. Assembly drawing of primary， tertiary and secondary mirrors

Fig. 16. Physical object of optical system

Fig. 17. Principle for wavefront aberration measurement of optical system

Fig. 18. Experimental setup for wavefront aberration measurement

Fig. 19. Measurement result of wavefront aberration

Fig. 20. Imaging experiment and effect demonstration