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Optical Engineering • Open Access

Impact of different cleaning processes on the laser damage threshold of antireflection coatings for Z-Backlighter optics at Sandia National Laboratories
Author(s): Ella S. Field; John C. Bellum; Damon E. Kletecka

Paper Abstract

We have examined how three different cleaning processes affect the laser-induced damage threshold (LIDT) of antireflection coatings for large dimension, Z-Backlighter laser optics at Sandia National Laboratories. Laser damage thresholds were measured after the coatings were created, and again 4 months later to determine which cleaning processes were most effective. Coatings that received cleaning exhibited the highest LIDTs compared to coatings that were not cleaned. In some cases, there is nearly a twofold increase in the LIDT between the cleaned and uncleaned coatings (19.4  J/cm2 compared to 39.1  J/cm2). Higher LIDTs were realized after 4 months of aging. The most effective cleaning process involved washing the coated surface with mild detergent, and then soaking the optic in a mixture of ethyl alcohol and deionized water. Also, the laser damage results indicate that the presence of nonpropagating (NP) damage sites dominates the LIDTs of almost every optic, despite the cleaning process used. NP damage sites can be attributed to defects such as nodules in the coating or surface contamination, which suggests that pursuing further improvements to the deposition or cleaning processes are worthwhile to achieve even higher LIDTs.

Paper Details

Date Published: 6 November 2014
PDF: 8 pages
Opt. Eng. 53(12) 122516 doi: 10.1117/1.OE.53.12.122516
Published in: Optical Engineering Volume 53, Issue 12
Show Author Affiliations
Ella S. Field, Sandia National Labs. (United States)
John C. Bellum, Sandia National Labs. (United States)
Damon E. Kletecka, Sandia National Labs. (United States)

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