STP799: Limits to the Validity of Evaluating a Quarter-Wave, High-Reflectance Multilayer Through Analysis of Its Secondary Structure

    Bennett, HE
    Michelson Laboratory, Physics Division Naval Weapons Center, China Lake, California

    Burge, DK
    Michelson Laboratory, Physics Division Naval Weapons Center, China Lake, California

    Pages: 6    Published: Jan 1983


    Abstract

    Information on the perfection of high-reflectance multilayer films can be obtained from a study of the secondary structure surrounding the principal reflectance maximum. The wavelengths at which the adjacent minima occur are a good indication of the correctness of the optical film thicknesses achieved in a quarter-wave multilayer stack. Calculations indicate that the depths of these minima are much more sensitive to absorption in the film layers than is the reflectance at the maximum. If the thicknesses are correct and if volume absorption in the film materials is the main source of decreased reflectance, excellent correlation is found between the measured peak reflectance and that calculated from the depth of the more easily measured secondary reflectance minima. Errors in film thickness or significant interface absorption arising from impurity segregation, surface plasmon excitation, or other sources complicate this simple picture, however, so that the peak reflectance should also be measured directly.

    Keywords:

    absorption, high-reflectance coatings, interface absorption, laser components, multilayer film evaluation, nonuniform film thicknesses, reflectance maximum


    Paper ID: STP37266S

    Committee/Subcommittee: F01.02

    DOI: 10.1520/STP37266S


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