Influence of defect shape on laser-induced damage in multilayer coatings
Atomic force microscopy (AFM) was used as a diagnostic for laser damage testing of lim-scale nodule defects in e-beam deposited HfO2/SiO{sub 2} multilayer mirror coatings. Earlier experiments in our laboratory showed that there was a significant increase in damage susceptibility for defects with heights greater than 0.6 {mu}m. In the present study, e-beam HfO{sub 2}/SiO{sub 2} HR coatings from two additional vendors were also studied. Atomic force microscopy characterization of the defects showed that the defect shape became less ``classic`` as the defect dimensions, especially height, increased. The characteristic shapes (spatter, multi-lobe, etc.) of the larger defects also varied between vendors. Using the AFM and optical microscopy, laser damage experiments (1064-nm, 3-ns pulses) were performed on various defects found in the coatings of the two new vendors. The data showed once again that the damage susceptibility increased as the height of the defect increased. There was also some difference between vendors in the damage susceptibility of the defects of a given size. Spatter defects, found predominantly in the coatings of one vendor showed the highest susceptibility to damage.
- Research Organization:
- Lawrence Livermore National Lab., CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 10173684
- Report Number(s):
- UCRL-JC-115161; CONF-9406168-2; ON: DE94016543
- Resource Relation:
- Conference: International symposium on optical interference coatings,Grenoble (France),6-14 Jun 1994; Other Information: PBD: Jun 1994
- Country of Publication:
- United States
- Language:
- English
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