STP799

    Preliminary Experimental Results of Spot Size Scaling in Laser Induced Damage to Optical Coatings

    Published: Jan 1983


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    Abstract

    The laser damage threshold of various thin film coatings has been assessed using 1.06 μm radiation at a pulse length of 6ns FWHM. Samples of conventional coatings of several materials have been tested as a function of film thickness and spot size. Beam diameters employed range from approximately 9μm and larger.

    From these preliminary data, previously observed scaling has been verified, i.e., thinner films are more damage resistant, while smaller spot sizes yield higher damage thresholds, as expected. The samples employed in these tests were conventional coatings of ThF4, ZrO2 and HfO2 as well as specially prepared “Low defect” coatings of Cerac and RAP grown ThF4. These “low defect” coatings are initial efforts and unfortunately showed no advantage over conventional coatings in terms of damage threshold.

    Keywords:

    Laser damage, thin films, spot size dependence, film thickness dependence, impurity damage, scaling


    Author Information:

    Stewart, AF
    Air Force Weapons Laboratory Kirtland Air Force Base, New Mexico

    Guenther, AH
    Air Force Weapons Laboratory Kirtland Air Force Base, New Mexico


    Paper ID: STP37278S

    Committee/Subcommittee: F01.02

    DOI: 10.1520/STP37278S


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