DocumentCode :
1083476
Title :
Ultraviolet damage resistance of dielectric reflectors under multiple-shot irradiation
Author :
Foltyn, Stephen R. ; Newnam, Brian E.
Author_Institution :
University of California, Los Alamos, NM, USA
Volume :
17
Issue :
10
fYear :
1981
fDate :
10/1/1981 12:00:00 AM
Firstpage :
2092
Lastpage :
2098
Abstract :
Multiple-shot damage thresholds of dielectric reflectors have been measured at 248 and 308 nm. Standard irradiation conditions were a 10 ns pulsewidth, a 0.6 mm spot diameter, and a 35 Hz pulse repetition frequency. The reflectors, from various sources, were composed of oxide and fluoride films. Although damage was generally initiated at visible film defects, there was no correlation between damage susceptibility and the appearance of these defects. At levels near threshold, damage was most often observed as an increase in white-light scatter of a site with no growth upon continued irradiation; at higher levels the damage site grew with successive shots. Test sites were subjected to at least 103shots and some sites received as many as 2.5 \\times 10^{4} shots; however, with only one exception, damage was found to occur within the first few shots or not at all. Reflectors at 248 nm typically had damage thresholds in the 1.0-1.8 J/cm2range with two samples exhibiting unexpectedly high thresholds of 2.8 and 3.0 J/cm2. In some cases, a subthreshold preirradiation treatment resulted in a 20-25 percent enhancement in damage resistance.
Keywords :
Dielectric radiation effects; Laser radiation effects; Optical reflection; Ultraviolet radiation effects; Coatings; Dielectric measurements; Electrical resistance measurement; Optical films; Optical filters; Optical scattering; Pulse measurements; Space vector pulse width modulation; Testing; Wavelength measurement;
fLanguage :
English
Journal_Title :
Quantum Electronics, IEEE Journal of
Publisher :
ieee
ISSN :
0018-9197
Type :
jour
DOI :
10.1109/JQE.1981.1070666
Filename :
1070666
Link To Document :
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