Fig. 1. Structural diagram of 355 nm/532 nm high-reflection film

Fig. 2. SEM images of micron-scale nodule defects produced by film material ejection. (a) Typical nodule morphology on film surface;(b) HfO₂ seed in nodule; (c) SiO₂ seed in nodule

Fig. 3. SEM images of submicron nodule defects produced by film material ejection. (a) Typical nodule morphology on film surface;(b) section of a nodule defect ; (c) section of another nodule defect

Fig. 4. TEM 3D reconstruction views of submicron nodule defect. (a) Front view; (b) side view

Fig. 5. Element distributions in submicron nodule defects measured by TEM-EDS. (a) HAADF image; (b) Hf; (c) Si; (d) O; (e) Na; (f) K

Fig. 6. SEM images of substrate defects. (a) Pit; (b) substrate crack after high temperature annealing

Fig. 7. Film defects caused by substrate defects. (a) SEM image showing porosity and peeling of bottom layer of film; (b) TEM image of nodule-like defect structure in coatings

Fig. 8. Element distributions of substrate impurities in Fig. 7(b) obtained by TEM-EDS. (a) Hf; (b) Si; (c) O; (d) Al

Fig. 9. TEM-EDS analysis for sputter damage pit caused by nodule defect in film after laser irradiation. (a) Morphology of damage pit; (b) element content and morphology of film layer far away from damage pit; (c) element content and morphology of damage pit edge; (d) morphology of damaged pit bottom

Fig. 10. SEM-EDS analysis of crack-like damage pit. (a) Crack-like damage; (b) cross-sectional morphology of crack-like damage;(c) elements in white area of substrate; (d) elements in non-damaged area of substrate