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Optical Engineering • Open Access

Shape dependence of laser–particle interaction-induced damage on the protective capping layer of 1 ω high reflector mirror coatings
Author(s): S. Roger Qiu; Mary A. Norton; John Honig; Alexander M. Rubenchik; Charles D. Boley; Amy Rigatti; Christopher J. Stolz; Manyalibo J. Matthews

Paper Abstract

The response of a potential candidate protective capping layer ( SiO 2 or Al 2 O 3 ) to laser exposure of 1 ω (1053 nm) to high-reflector silica-hafnia multilayer coatings in the presence of variously shaped Ti particles is investigated by combining laser damage testing and numerical modeling. Each sample is exposed to a single oblique angle (45 deg) laser shot (p-polarization, 10    J / cm 2 , 14 ns) in the presence of spherically or irregularly shaped Ti particles on the surface. The two capping layers show markedly different responses. For the spherical particles, the Al 2 O 3 cap layer exhibits severe damage, with the capping layer becoming completely delaminated at the particle locations. The SiO 2 capping layer is only mildly modified by a shallow depression, likely due to plasma erosion. The different response of the capping layer is attributed to the large difference in the thermal expansion coefficient of the materials, with that of the Al 2 O 3 about 15 times greater than that of the SiO 2 layer. For the irregular particles, the Al 2 O 3 capping layer d

Paper Details

Date Published: 24 October 2016
PDF: 7 pages
Opt. Eng. 56(1) 011108 doi: 10.1117/1.OE.56.1.011108
Published in: Optical Engineering Volume 56, Issue 1
Show Author Affiliations
S. Roger Qiu, Lawrence Livermore National Laboratory (United States)
Mary A. Norton, Lawrence Livermore National Laboratory (United States)
John Honig, Lawrence Livermore National Laboratory (United States)
Alexander M. Rubenchik, Lawrence Livermore National Laboratory (United States)
Charles D. Boley, Lawrence Livermore National Laboratory (United States)
Amy Rigatti, University of Rochester (United States)
Christopher J. Stolz, Lawrence Livermore National Laboratory (United States)
Manyalibo J. Matthews, Lawrence Livermore National Laboratory (United States)


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