Fig. 1. Aspheric surface parallel grinding method

Fig. 2. Ultra-precision grinding machine for large aperture aspheric optics

Fig. 3. Dressing arc diamond wheel by roll abrading^[12]. (a) Principle of dressing; (b) dressing equipment

Fig. 4. In-situ measurement and evaluation of 3D shape error of diamond wheel^[13]. (a) Principle of in-situ measurement of 3D shape error; (b) 3D outline error; (c) roundness error

Fig. 5. In-situ measurement and compensation of aspheric surface shape^[5,14]. (a) Trajectory of in-situ measurement; (b) physical image of in-situ detection; (c) compensation process principle

Fig. 6. Results of large aperture aspheric surface grinding

Fig. 7. Schematic figure and physical picture of plane rapid polishing. (a) Principle diagram; (b) physical picture

Fig. 8. Plane rapid polishing results. (a) Surface roughness (RMS is 0.42 nm); (b) optimal profile accuracy (PV is 0.24λ)

Fig. 9. Bonnet polishing picture and principle for off-axis aspheric lens. (a) Bonnet polishing picture; (b) principle diagram

Fig. 10. Serialization of bonnet tools^[23]. (a) Tool picture; (b) tool structure design and simulation

Fig. 11. Bonnet dressing picture and mathematical model^[26]. (a) Bonnet dressing picture; (b) bonnet dressing mathematical model

Fig. 12. Results of aspheric lens by bonnet polishing. (a) Initial surface shape; (b) conformal polishing surface shape; (c) fast correction polishing surface shape

Fig. 13. Principle of full-aperture ring polishing process

Fig. 14. Kinematics model of full-aperture continuous polishing process. (a) Kinematics; (b) sliding distance

Fig. 15. Method and result of measuring the lap shape error. (a) Measuring method; (b) measuring result

Fig. 16. Passivation state images and characteristic value change curve of pitch plate for different working time

Fig. 17. Ф5 m full aperture deterministic continuous polisher and workpiece surface figure results. (a) Polisher photograph;(b) workpiece surface figure

Fig. 18. Magnetorheological cell technology and results. (a) Integrated follow-up circulating system; (b) stable flow control of magnetorheological fluid; (c) modular series polishing head (diameter is 20-400 mm); (d) wide range magnetorheological processing capability

Fig. 19. Continuous phase plate processed by magnetorheological method. (a) Designed continuous phase plate; (b) machining residual diagram of continuous phase plate

Fig. 20. Ion beam polishing machine and its processing principle. (a) Principle of precision shaping; (b) ion beam polishing machine

Fig. 21. Diagrams of adaptive step trajectory segment partition algorithm^[54]. (a) Same step size path segment; (b) adaptive step size path segment

Fig. 22. Deterministic verification experiment for ion beam polishing. (a) Original surface (PV is 0.903λ); (b) simulation result (PV is 0.360λ); (c) processed result (PV is 0.364λ)

Fig. 23. Result of ion beam polishing for large aperture optical elements

Fig. 24. Contours of residual ripples obtained by three paths^[26]. (a) Raster path (RMS is 18.134 nm); (b) circle path (RMS is 18.378 nm); (c) random path (RMS is 50.152 nm)

Fig. 25. Control technology for middle frequency error. (a) Removal function stability control^[8]; (b) smoothing correction for middle and high frequency errors^[61]

Fig. 26. Aspheric smoothing results. (a) 430 mm×430 mm aspheric lens; (b) middle frequency error PSD1 (RMS is 1.67 nm)

Fig. 27. Schematic diagram of single point diamond fly-cutting process and fly-cutting equipment

Fig. 28. Monitoring platform and simulation model of dynamic performace of fly-cutting machine

Fig. 29. Simulation results of BDT of KDP crystal^[67]. (a) Stress state in cutting zone; (b) variation of BDT with cutting direction

Fig. 30. Measurement results of KDP surface for fly-cutting. (a) Low frequency error (PV is 2.1λ); (b) middle frequency PSD1 (RMS is 3.14 nm); (c) middle frequency PSD2 (RMS is 0.68 nm); (d) roughness (RMS is 0.61 nm)

Fig. 31. Two typical grinding defects. (a) Regularly distributed dotted line defects; (b) occasional deep pit defect

Fig. 32. Depth of grinding subsurface defects

Fig. 33. Morphology and particle size distribution of ceria polishing particles. (a) Particle morphology; (b) particle size distribution diagram

Fig. 34. Content of metallic elements on surface of fused silica treated by different methods^[82]. (a) Ce content after HF/BOE etching; (b) metallic element content after HNO₃ etching

Fig. 35. Effect of chemical etching depth on surface roughness and laser damage threshold of fused silica^[83]. (a) Surface roughness;(b) laser damage threshold

Fig. 36. Laser-induced damage performance of KDP surface defects^[88]. (a) In-situ defect damage test; (b) damage threshold of surface defects

Fig. 37. Influence of tool wear on surface defects of crystal. (a) Defect-free cutting tool and crack-free KDP surface; (b) wear tool and microstructure of machined surface