STP1117

    Large Area Laser Conditioning of Dielectric Thin Film Mirrors

    Published: Jan 1990


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    Abstract

    The laser conditioning of dielectric thin film HR coatings has been studied as a practical method for the improvement of the damage thresholds of large area (1.1 m dia.) high power 1064 nm laser mirrors on the LLNL 120 kJ, 100 TW Nova laser system. Both HfO2/SiO2 and ZrO2/SiO2HR coatings were conditioned by rastering with a small (∼0.2 mm) diameter beam from a pulsed (18 Hz, 8 ns) Nd-YAG laser (1064 nm). The samples were rastered at various fluences below the unconditioned damage threshold and subsequently damage tested. Large area conditioning studies were also performed using a large aperture beam of the Nova laser. The laser conditioning effect was found to be permanent. Improvements in damage threshold due to conditioning were as high as a factor of 2.7 and were dependent on the conditioning parameters. A model for the conditioning effect is proposed based on the emptying of electronic defect levels within the bandgap of the dielectric materials.

    Keywords:

    electronic defects, halfnia, HR coatings, laser conditioning, laser damage, silica, zirconia


    Author Information:

    Kozlowski, MR
    Lawrence Livermore National Laboratory University of California, Livermore, CA

    Wolfe, CR
    Lawrence Livermore National Laboratory University of California, Livermore, CA

    Staggs, MC
    Lawrence Livermore National Laboratory University of California, Livermore, CA

    Campbell, JH
    Lawrence Livermore National Laboratory University of California, Livermore, CA


    Paper ID: STP26505S

    Committee/Subcommittee: E13.15

    DOI: 10.1520/STP26505S


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