STP759

    Infrared Wavelength Modulation Spectroscopy of Laser Window Materials

    Published: Oct 1981


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    Abstract

    We have previously shown that the infrared wavelength modulation system that we have developed is capable of measuring the complete spectral distribution of the extrinsic absorption in highly transparent solids at levels of 10−5 cm−1 in the spectral range from 2.5 to 12 microns [1]. The previous measurement techniques that were employed for KBr and KC have been extended to other crystalline systems which are of interest in light guiding applications, namely: CaF2, LiF, NaC, NaF, LaF3, BaF2, MgF2, SrF2, and MgO. Rich and varied absorption structures were observed in all of these crystals enabling an identification of volume and surface absorption. Similar dominant bands are observed in many of these substances indicating the presence of common impurities regardless of the crystal and the origin of its growth. However, varied fine structures are observed in different crystals which are indicative of the individual characteristics of the chemistry of the crystal preparation. These measurements were performed in laboratory and dry N2 ambients and readily show the physisorption and desorption of surface contaminants. In appropriate materials, measurements were extended into the intrinsic multiphonon region.

    Keywords:

    Extrinsic and intrinsic infrared absorption, volume and surface impurities, infrared wavelength modulation, CaF, 2, LiF, NaCℓ, NaF, LaF, 3, BaF, 2, MgF, 2, SrF, 2, MgO, laser windows


    Author Information:

    Braunstein, R
    University of California, Los Angeles, California

    Kim, RK
    University of California, Los Angeles, California

    Braunstein, M
    University of California, Los Angeles, California


    Paper ID: STP36994S

    Committee/Subcommittee: F01.02

    DOI: 10.1520/STP36994S


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