CW laser damage testing of RAR nano-textured fused silica and YAG

Bruce D. Macleod, Douglas S. Hobbs, Anthony D. Manni, Ernest Sabatino, David M. Bernot, Sage Defrances, Joseph A. Randi, III, Jeffrey Thomas

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations

Abstract

A study of the continuous wave (CW) laser induced damage threshold (LiDT) of fused silica and yttrium aluminum garnet (YAG) optics was conducted to further illustrate the enhanced survivability within high power laser systems of an anti-reflection (AR) treatment consisting of randomly distributed surface relief nanostructures (RAR). A series of three CW LiDT tests using the 1070nm wavelength, 16 KW fiber laser test bed at Penn State Electro-Optic Center (PSEOC) were designed and completed, with improvements in the testing protocol, areal coverage, and maximum exposure intensities implemented between test cycles. Initial results for accumulated power, stationary site exposures of RAR nano-textured optics showed no damage and low surface temperatures similar to the control optics with no AR treatment. In contrast, optics with thin-film AR coatings showed high surface temperatures consistent with absorption by the film layers. Surface discriminating absorption measurements made using the Photothermal Common-path Interferometry (PCI) method, showed zero added surface absorption for the RAR nanotextured optics, and absorption levels in the 2-5 part per million range for thin-film AR coated optics. In addition, the surface absorption of thin-film AR coatings was also found to have localized absorption spikes that are likely pre-cursors for damage. Subsequent CW LiDT testing protocol included raster scanning an increased intensity focused beam over the test optic surface where it was found that thin-film AR coated optics damaged at intensities in the 2 to 5 MW/cm2 range with surface temperatures over 250C during the long-duration exposures. Significantly, none of the 10 RAR nano-textured fused silica optics tested could be damaged up to the maximum system intensity of 15.5 MW/cm2, and surface temperatures remained low. YAG optics tested during the final cycle exhibited a similar result with RAR nano-textured surfaces surviving intensities over 3 times higher than thin-film AR coated surfaces. This result was correlated with PCI measurements that also show zero-added surface absorption for the RAR nano-textured YAG optics.

Original languageEnglish (US)
Title of host publication49th Annual Laser Damage Symposium Proceedings - Laser-Induced Damage in Optical Materials 2017
EditorsGregory J. Exarhos, Vitaly E. Gruzdev, Joseph A. Menapace, Detlev Ristau, M.J. Soileau
PublisherSPIE
ISBN (Electronic)9781510613621
DOIs
StatePublished - Jan 1 2017
Event49th Annual Laser Damage Symposium Proceedings - Laser-Induced Damage in Optical Materials 2017 - Boulder, United States
Duration: Sep 24 2017Sep 27 2017

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume10447
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X

Other

Other49th Annual Laser Damage Symposium Proceedings - Laser-Induced Damage in Optical Materials 2017
CountryUnited States
CityBoulder
Period9/24/179/27/17

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All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

Cite this

Macleod, B. D., Hobbs, D. S., Manni, A. D., Sabatino, E., Bernot, D. M., Defrances, S., Randi, III, J. A., & Thomas, J. (2017). CW laser damage testing of RAR nano-textured fused silica and YAG. In G. J. Exarhos, V. E. Gruzdev, J. A. Menapace, D. Ristau, & M. J. Soileau (Eds.), 49th Annual Laser Damage Symposium Proceedings - Laser-Induced Damage in Optical Materials 2017 [1044705] (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 10447). SPIE. https://doi.org/10.1117/12.2280498