23 July 1982 Radiation Effects In Dielectrically Enhanced Reflectance Mirrors
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Proceedings Volume 0328, Laser and Laser Systems Reliability; (1982) https://doi.org/10.1117/12.933891
Event: 1982 Los Angeles Technical Symposium, 1982, Los Angeles, United States
Abstract
Thin-film dielectric coatings for laser optics have been exposed to several types of radiation. The forms of radiation (UV, protons, and electrons) were chosen to deposit energy in the coatings and their substrates. Certain multilayer coatings for mirrors improved after irradiation in vacuum. Their absorptance near 2.7 micrometers in the infrared decreased after exposure to UV and visible light for as much as 1600 hours. The design (Al203/Si)2AgCrMo showed the most improvement, its absorption being roughly halved by this UV radiation exposure. Different changes were noted, however, in other samples of this design exposed to 25-keV protons and 40-keV electrons. Fluences were >1016 cm-2 and dosage >109 rad(Si). Similar results were obtained with the designs (SiOx/Si)nAgCrMo and (Al203/ZnS)4AgCrMo. This last design is not as stable as the other two, but was pursued as an improvement over its predecessors. The individual constituents of these coatings have also been irradiated in other experiments as single-layer films on CaF2 windows. Changes in absorptance and refractive index have been observed there. Attempts have been made to correlate the changes observed by laser absorption calorimetry, with results obtained in surface studies such as XPS. Compositional changes in some materials are implied.
© (1982) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
L. B. Fogdall, S. S. Cannaday, T. M. Donovan, "Radiation Effects In Dielectrically Enhanced Reflectance Mirrors", Proc. SPIE 0328, Laser and Laser Systems Reliability, (23 July 1982); doi: 10.1117/12.933891; https://doi.org/10.1117/12.933891
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