Fig. 1. Initial damage morphologies on rear surface of fused silica optics^[6]

Fig. 2. Initial damage pits on rear surface made by 1 on 1 method. (a) Distribution of initial damage pits; (b) particle size distribution

Fig. 3. Typical SEM morphology of thermal explosion center at initial damage pit

Fig. 4. Damage growth of initial damage pit on rear surface

Fig. 5. Top view and side view for damage growth pit on rear surface of fused silica^[9]. (a) Top view; (b) side view

Fig. 6. Transverse and depth distribution morphologies of damage growth pits based on synchrotron radiation X-ray microtomography^[11]

Fig. 7. Test results of different initial damage points. (a) Damage growth threshold; (b) damage growth probability

Fig. 8. Size of damage point on surface of fused silica optics varying with laser irradiation time^[12]

Fig. 9. Damage growth characteristics of rear surface of fused silica. (a) Relationship between damage area and laser irradiation time; (b) relationship damage growth coefficient and laser energy density

Fig. 10. Typical physical stages in rear surface damage eruption of fused silica optics

Fig. 11. Four types of typical damage splashing particles on rear surface of fused silica^[16]. (a) First kind; (b) second kind; (c) third kind; (d) fourth kind

Fig. 12. Initial damage point image, transient damage point image after 21 ns pulse irradiation and damage growth image of final state obtained by time-resolved imaging^[17]. (a) Initial damage point image; (b) transient damage point image after 21 ns pulse irradiation; (c) damage growth image of final state

Fig. 13. Distribution of contamination impurity defects on surface of fused silica optics and surface high-density damage pits caused by them. (a) Distribution of contamination impurity defects; (b) surface high-density damage pits caused by contamination impurity defects

Fig. 14. Typical scratch morphologies on surface of fused silica. (a) Linear continuous scratch; (b) disconnected pit scratch; (c) hertz scratch

Fig. 15. Chemical structure defects on surface of fused silica and laser damage induced by them^[28]. (a) Plastic indentation produced by 0.5 N indentation meter; (b) fast fluorescence signal in plastic indentation; (c) laser damage induced by chemical structural defects

Fig. 16. Influence of different temperatures on band gap and absorption coefficient of fused silica^[31]. (a) Band gap; (b) absorption coefficient

Fig. 17. Absorption wavefront model for damage initiation of fused silica^[32]

Fig. 18. Hypothetical time line model for laser-induced damage events^[33]

Fig. 19. Kinetic process of nanosecond laser induced damage in fused silica optics

Fig. 20. Difference of energy release of plasmonic fireballs induced by damage of input and rear surfaces of optics^[30]

Fig. 21. Typical distribution characteristics of damage pits on rear surface of fused silica

Fig. 22. Fabrication flow of surface of fused silica optics

Fig. 23. Process of observing subsurface damage layer in grinding process by magnetorheological pit method. (a) Magnetorheological pit; (b) depth profile of magnetorheological pit; (c) subsurface damage observed by microscope

Fig. 24. Subsurface defect diagram after small tool polishing and mechanism analysis for defect generation^[36]. (a) Subsurface defect diagram after small tool polishing; (b) mechanism analysis for defect generation

Fig. 25. Schematic diagrams of magnetorheological polishing and elastic emission polishing. (a) Magnetorheological polishing;(b) elastic emission polishing

Fig. 26. Schematic diagrams of ion beam polishing and jet polishing. (a) ion beam polishing; (b) jet polishing

Fig. 27. Diagram for technological process and technical principle of AMP

Fig. 28. Simulation of microcrack morphology scale and transport effect of internal secondary pollution product (SiF₆^2-) in different stages of AMP treatment^[50]

Fig. 29. Characteristics of wide-band gap inorganic precipitation on rear surface and damage threshold of different types of inorganic compounds^[54]. (a) Microscopic morphology; (b) fast fluorescence characteristics; (c) induced damage morphology; (d) large scale damage pit; (e) damage threshold of different types of inorganic compounds

Fig. 30. Comparison of damage density between NIF's AMP technology and other polishing processes^[32]

Fig. 31. Schematic diagram of CEP technology

Fig. 32. Surface morphologies of fused silica optics after original polishing, DCE and CEP, and test results of damage probability and roughness under different treatment processes. (a) Surface morphology of fused silica optics after original polishing; (b) surface morphology of fused silica optics after DCE; (c) surface morphology of fused silica optics after CEP; (d) test results of damage probability under different treatment processes; (e) test results of roughness under different treatment processes

Fig. 33. Non-evaporative repair and evaporative repair

Fig. 34. Morphology difference of surface scratches before and after modification by HF acid etching^[50]. (a) Before modification;(b) after modification

Fig. 35. Schematic diagram of photo-thermal weak absorption detection technology

Fig. 36. Statistical numerical correlation between average photo-thermal weak absorption coefficient and damage density of rear surface of fused silica under 12 J/cm² luminous flux

Fig. 37. Basic principle of photofluorescence defect detection technique

Fig. 38. Comparison of detection results of white bright field microscopic imaging and ultraviolet laser induced fluorescence imaging. (a) White light field microscopic imaging; (b) ultraviolet laser induced fluorescence imaging

Fig. 39. Detection result of confocal three-dimensional imaging for fluorescence defects on surface of fused silica (two-dimensional fluorescence detection result is shown in upper left corner)

Fig. 40. Schematic diagram of R on 1 test method for laser damage threshold of optics

Fig. 41. Schematic diagram of 1 on 1 testing method

Fig. 42. Raster scan and spot splicing mode used in damage density testing. (a) Raster scan; (b) spot splicing mode