STP689

    Photoacoustic Spectroscopy Studies of Thin Film Coatings on Laser Windows

    Published: Jan 1979


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    Abstract

    Photoacoustic spectroscopy (PAS) studies have been made of TlI and graded PbF2-TlI coatings on KCl. Wavelength dependent PAS studies on the TlI absorption edge indicate impurities in TlI in the graded coating and/or the existence of cubic TlI layers. PAS wave-length studies were made on a solid ZnSe window and various ZnSe coatings on CaF2. Wavelength dependent studies show poorer stoichiometry as the coating gets thinner. Frequency dependent PAS studies at 440 nm on the solid and thin film ZnSe all showed a signal dependence of S = Af-1. Theoretical calculations based on the Rosencwaig-Gersho theory show that these results are consistent if β is greater than 500 cm-1 for ZnSe at 440 nm.

    Keywords:

    Absorption edge, CaF, 2, KCl, optical absorption coefficient, optoacoustic spectroscopy, PbF, 2, photoacoustic spectroscopy, TlI, ZnSe


    Author Information:

    Fernelius, NC
    University of Dayton Research Institute 300 College, Dayton, Ohio

    Walsh, DA
    University of Dayton Research Institute 300 College, Dayton, Ohio


    Paper ID: STP39102S

    Committee/Subcommittee: F01.02

    DOI: 10.1520/STP39102S


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