How reduced vacuum pumping capability in a coating chamber affects the laser damage resistance of HfO₂/SiO₂ antireflection and high reflection coatings.

Journal Article · Wed Jun 01 00:00:00 EDT 2016 · Proceedings of SPIE - The International Society for Optical Engineering

DOI:https://doi.org/10.1117/12.2194131· OSTI ID:1259475

Field, Ella Suzanne ^[1]; Bellum, John Curtis ^[1]; Kletecka, Damon E. ^[1]

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1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

Optical coatings with the highest laser damage thresholds rely on clean conditions in the vacuum chamber during the coating deposition process. A low base pressure in the coating chamber, as well as the ability of the vacuum system to maintain the required pressure during deposition, are important aspects of limiting the amount of defects in an optical coating that could induce laser damage. Our large optics coating chamber at Sandia National Laboratories normally relies on three cryo pumps to maintain low pressures for e-beam coating processes. However, on occasion, one or more of the cryo pumps have been out of commission. In light of this circumstance, we explored how deposition under compromised vacuum conditions resulting from the use of only one or two cryo pumps affects the laser-induced damage thresholds of optical coatings. Finally, the coatings of this study consist of HfO₂ and SiO₂ layer materials and include antireflection coatings for 527 nm at normal incidence, and high reflection coatings for 527 nm, 45⁰ angle of incidence (AOI), in P-polarization (P-pol).

• Research Organization: Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: AC04-94AL85000
• OSTI ID: 1259475
• Report Number(s): SAND-2016-5601J; 642192
• Journal Information: Proceedings of SPIE - The International Society for Optical Engineering, Vol. 9632; ISSN 0277-786X
• Publisher: SPIE
• Country of Publication: United States
• Language: English