Fig. 1. Schematic of nanosecond laser damage time-resolved measurement device

Fig. 2. Transmittance curve of anti-reflection coating

Fig. 3. Working states of anti-reflection coating. (a) Forward process when placing coating on laser incidence surface; (b) reverse process when placing coating on laser exit surface

Fig. 4. Damage morphologies in forward process. (a) Pit without layer peeling-off; (b) pit with layer peeling-off; (a1) and (b1) are SEM images of Figs.4(a) and (b), respectively; (a2) and (b2) are enlarged images of pits in Figs.4(a1) and (b1), respectively; (a3) and (b3) are SEM images of undamaged areas shown in dashed boxes in Figs.4(a1) and (b1), respectively; (a4) and (b4) are SEM images of color change areas shown in dashed boxes in Figs.4(a1) and (b1), respectively; (a5) and (b5) are cross-sectional views of pits in Figs.4(a) and (b), respectively; (b6) is cross-sectional view of layer peeling-off boundary at white dashed line in Fig.4(b1)

Fig. 5. Damage morphologies in reverse process. (a) Pit without layer peeling-off; (b) pit with layer peeling-off; (a1) and (b1) are SEM images of Figs.5(a) and (b), respectively; (a2) and (b2) are enlarged images of pits in Figs.5(a1) and (b1), respectively; (a3) and (b3) are SEM images of undamaged areas shown in dashed boxes in Figs.5(a1) and (b1), respectively; (a4) and (b4) are SEM images of color change areas shown in dashed boxes in Figs.5(a1) and (b1), respectively; (a5) is cross-sectional view of pit boundary shown in white dashed boxes in Fig.5(a2); (b5) is surface SEM image of pit with layer peeling-off after local FIB in Fig.5(b1); (b6) is cross-sectional view of pit in Fig.5(b2); (b7) is cross-sectional view of pit boundary shown in white dashed boxes in Fig.5(b5); (b8) is cross-sectional view of layer peeling-off boundary shown in dashed boxes in Fig.5(b5)

Fig. 6. Size statistics of various damage pits and peeling-off coating layer. (a) Damage center pit; (b) peeling-off coating layer

Fig. 7. Damage dynamic process of pits with layer peeling-off in forward process

Fig. 8. Damage dynamic process of pits without layer peeling-off in forward process

Fig. 9. Dynamic damage process of pits with layer peeling-off in reverse process

Fig. 10. Dynamic damage process of pits without layer peeling-off in reverse process

Fig. 11. Electric field simulations for forward and reverse processes of anti-reflection coatings. (a) Forward process; (b) reverse process

Fig. 12. Shielding effect of plasma on laser pulse. (a) Forward process; (b) reverse process

Fig. 13. Shock wave radius versus time corresponding to different damage morphologies (points and circles represent data, and lines represent fitted curves)