Paper
14 July 1995 Degradation of optical components in laser machines for manufacturing
Michael J. Dahmen, C. R. Haas, Ernst-Wolfgang Kreutz, David A. Wesner
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Abstract
Coated ZnSe optical components are irradiated with high-power, pulsed CO2 laser radiation at fluences up to 250 J/cm2. The components are characterized at various stages of irradiation by optical microscopy, interferometric microscopy, profilometry, surface chemical analysis (x-ray photoemission and Auger electron spectroscopy), and surface structural analysis (micron-Raman spectroscopy). Two types of coating damage occur within the irradiated area of the component: a breaking apart of the ZnSe overlayer of the coating system over relatively large areas resulting in a network structure, and the formation of isolated craters of diameter approximately 30-50 micrometers extending in depth of approximately 5 micrometers through the coating system down to the ZnSe substrate. Chemically, the irradiated area is characterized by an oxidation of both Zn and Se and an increase in the stoichiometric ratio of Zn and Se. These effects are especially pronounced at the crater defects, and are attributed to localized optical absorption, leading to thermal stress and chemical reactions of Zn and Se with atmospheric or absorbed water and/or oxygen. Structually, the coatings exhibit a polycrystalline structure with no orientation of the individual grains. During irradiation the grain size diminishes giving, in addition, indication for built-in stress and partial melting at high laser fluences.
© (1995) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Michael J. Dahmen, C. R. Haas, Ernst-Wolfgang Kreutz, and David A. Wesner "Degradation of optical components in laser machines for manufacturing", Proc. SPIE 2428, Laser-Induced Damage in Optical Materials: 1994, (14 July 1995); https://doi.org/10.1117/12.213700
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KEYWORDS
Selenium

Optical components

Zinc

Coating

Pulsed laser operation

Absorption

Laser safety

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