Fig. 1. Reflection spectrum of HfO₂/SiO₂ high-reflection film under condition of 45° incidence of S-polarized light

Fig. 2. Statistical results of LIDT for untreated and pre-treated samples under laser irradiation with different pulse widths. (a) 1 ps laser; (b) 10 ps laser; (c) 20 ps laser

Fig. 3. Influence of pre-treatment on internal defect density and defect threshold of sample. Comparison of damage probability distributions and fitting results of sample before and after pre-treatment under (a) 1 ps, (b) 10 ps and (c) 20 ps laser irradiation; (d) statistical results of defect average LIDT; (e) statistical results of defect density

Fig. 4. Typical damage morphologies of samples before and after pre-treatment under laser irradiation with different pulse widths

Fig. 5. Typical damage morphologies of untreated samples under laser irradiation with different pulse widths

Fig. 6. Damage characteristics of flat-bottom pits irradiated by lasers with different pulse widths under near-threshold energy density, and electric field intensity distribution of sample. (a)‒(c) Damage morphologies and cross-sectional images of flat-bottom pits; (d) electric field intensity distribution of sample when incident light is in S polarization state at angle of 45°

Fig. 7. Two-dimensional model diagram of high-reflection coating with defects

Fig. 8. Peak NeT and T_l versus EgD and their evolution characteristics under 10 ps laser irradiation. (a) Peak NeT and T_l versus EgD;

Fig. 9. NeT and T_l after 500 ps laser pre-treatment. (a) NeT; (b) T_l

Fig. 10. EgD and NeT before and after 500 ps laser pre-treatment. (a) Calculated EgD; (b) evolution of NeT under 10 ps laser irradiation

Fig. 11. Influence of pre-treatment on evolution law of NeT and its peak value. Evolution of NeT in 500 ps pre-treated sample under (a) 10 ps laser irradiation with energy density of 6.2 J/cm² and (b) 20 ps laser irradiation with energy density of 8.4 J/cm²; (c) calculated peak NeT in Figs.11(a) and (b)