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Title: Shape dependence of laser–particle interaction-induced damage on the protective capping layer of 1 ω high reflector mirror coatings

The response of a potential candidate protective capping layer (SiO 2 or Al 2O 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°) 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 2O 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 2O 3 about 15 times greater than that of the SiO 2 layer. For the irregular particles, the Al 2O 3 capping layer displays minimal to no damage while the SiO 2 capping layer is significantly damaged. In conclusion, the difference is due to the disparity inmore » mechanical strength with Al 2O 3 possessing approximately 10 times higher fracture toughness.« less
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [1] ;  [1]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. Univ. of Rochester, Rochester, NY (United States)
Publication Date:
Report Number(s):
LLNL-JRNL-691078
Journal ID: ISSN 0091-3286; 818773
Grant/Contract Number:
AC52-07NA27344
Type:
Accepted Manuscript
Journal Name:
Optical Engineering
Additional Journal Information:
Journal Volume: 56; Journal Issue: 1; Journal ID: ISSN 0091-3286
Publisher:
SPIE
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; Protective coating layer; Contamination; High reflector, Multilayer coatings; Laser damage; Plasmas; ; 1053 nm; High peak power laser
OSTI Identifier:
1463025

Qiu, S. Roger, Norton, Mary A., Honig, John, Rubenchik, Alexander M., Boley, Charles D., Rigatti, Amy, Stolz, Christopher J., and Matthews, Manyalibo J.. Shape dependence of laser–particle interaction-induced damage on the protective capping layer of 1 ω high reflector mirror coatings. United States: N. p., Web. doi:10.1117/1.OE.56.1.011108.
Qiu, S. Roger, Norton, Mary A., Honig, John, Rubenchik, Alexander M., Boley, Charles D., Rigatti, Amy, Stolz, Christopher J., & Matthews, Manyalibo J.. Shape dependence of laser–particle interaction-induced damage on the protective capping layer of 1 ω high reflector mirror coatings. United States. doi:10.1117/1.OE.56.1.011108.
Qiu, S. Roger, Norton, Mary A., Honig, John, Rubenchik, Alexander M., Boley, Charles D., Rigatti, Amy, Stolz, Christopher J., and Matthews, Manyalibo J.. 2016. "Shape dependence of laser–particle interaction-induced damage on the protective capping layer of 1 ω high reflector mirror coatings". United States. doi:10.1117/1.OE.56.1.011108. https://www.osti.gov/servlets/purl/1463025.
@article{osti_1463025,
title = {Shape dependence of laser–particle interaction-induced damage on the protective capping layer of 1 ω high reflector mirror coatings},
author = {Qiu, S. Roger and Norton, Mary A. and Honig, John and Rubenchik, Alexander M. and Boley, Charles D. and Rigatti, Amy and Stolz, Christopher J. and Matthews, Manyalibo J.},
abstractNote = {The response of a potential candidate protective capping layer (SiO2 or Al2O3) 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°) laser shot (p-polarization, ~10 J/cm2, 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 Al2O3 cap layer exhibits severe damage, with the capping layer becoming completely delaminated at the particle locations. The SiO2 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 Al2O3 about 15 times greater than that of the SiO2 layer. For the irregular particles, the Al2O3 capping layer displays minimal to no damage while the SiO2 capping layer is significantly damaged. In conclusion, the difference is due to the disparity in mechanical strength with Al2O3 possessing approximately 10 times higher fracture toughness.},
doi = {10.1117/1.OE.56.1.011108},
journal = {Optical Engineering},
number = 1,
volume = 56,
place = {United States},
year = {2016},
month = {10}
}