STP1117: The Response of Multilayer Dielectric Coatings to Low Fluence Ultraviolet Light Exposure

    Sanders, VE
    Los Alamos National Laboratory, Los Alamos, New Mexico

    Early, JW
    Los Alamos National Laboratory, Los Alamos, New Mexico

    Leamon, W
    Los Alamos National Laboratory, Los Alamos, New Mexico

    Pages: 7    Published: Jan 1990


    Multilayer dielectric high-reflectance coatings were investigated for potential application in a high-average-power, 1-μm wavelength, free-electron laser oscillator. Of concern are the ultraviolet harmonics of the primary wavelength generated within the oscillator that tend to degrade the dielectric coatings. These coatings are required to be high reflecting and low absorbing with respect to the 1-μm wavelength and resist degradation/damage from the ultraviolet harmonics.

    A KrF excimer laser was used to generate the low fluence ultraviolet light at 248-nm wavelength, a wavelength that simulates the fourth harmonic of the 1-μm free-electron laser. A variety of candidate dielectric oxide thin film materials are compared in this report. In each multilayer dielectric high reflector measured, a candidate high-index dielectric material is used in combination with SiO2 as the low-index material. Damage test measurements are reported for the 248-nm wavelength with HfO2 being the high-index material with significantly the best results.


    excimer laser damage, free-electron laser optics, laser damage, multilayer dielectric coating, ultraviolet damage

    Paper ID: STP26521S

    Committee/Subcommittee: E13.15

    DOI: 10.1520/STP26521S

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