Fig. 1. Aspheric departure

Fig. 2. Aspheric slope

Fig. 3. Process flow of combined processing

Fig. 4. Mill-grinding process of optical parts

Fig. 5. Results of grinding

Fig. 6. Schematic diagram of bonnet polishing

Fig. 7. Bonnet polishing

Fig. 8. Schematic diagram of pitch smoothing

Fig. 9. Results after first combined process. (a) Surface error; (b) Zernike residual

Fig. 10. Results after second combined process. (a) Surface error; (b) Zernike residual

Fig. 11. Results after third combined process. (a) Surface error; (b) Zernike residual

Fig. 12. Comparison of PSD curves

Fig. 13. Actual detection optical path

Fig. 14. Schematic diagram of distortion correction. (a) Physical coordinates; (b) Null lens testing; (c) CCD coordinates