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Very high damage threshold Al2O3/SiO2 dielectric coatings for excimer lasers

 

Bennett, H.E.; Chase, L.L. ; Society of Photo-Optical Instrumentation Engineers -SPIE-, Bellingham/Wash.:
Laser-Induced Damage in Optical Materials 1993. Proceedings
Bellingham/Wash.: SPIE, 1994 (SPIE Proceedings Series 2114)
ISBN: 0-8194-1407-7
pp.325-334
Laser-Induced Damage in Optical Materials Symposium <25, 1993, Boulder/Colo.>
Annual Boulder Damage Symposium <25, 1993, Boulder/Colo.>
Annual Symposium on Optical Materials for High-Power Lasers <25, 1993, Boulder/Colo.>
English
Conference Paper
Fraunhofer IOF ()
Dünne optische Schicht; excimer laser optics; Excimer-Laser-Optik; fluoride thin films; Fluoridschicht; laser induced damage threshold; Laserzerstörschwelle; optical coating; optical thin films; oxide thin films; Oxidschicht; ultraviolet spectral region; ultravioletter Spektralbereich; UV

Abstract
In the EUREKA EU205 project the target products are industrial excimer lasers in the average power range of one kilowatt or more. The high power optical components and dielectric coatings have to be developed in close adaption to cavity design (optics), beam relay optics, mask imaging optics, and masks. Therefore, we used ultra low loss conventional e-beam evaporation for Al2O3/SiO2 dielectric multilayers. Based on a fundamental coating technique, both multilayer mean background absorption and absorption at localized spikes have been reduced drastically. The resulting KrF laser damage threshold of HR coatings is 16 J/cm2 (1-on-1, 30ns, EMG-202-MSC). Measurements have been performed with an automated damage testing facility, being part of the EUREKA programm. Multilayers have been characterized by Atomic Force Microscopy, Photothermal Microscopy, absorption measurements, and Spectroscopy of Sputtered Neutrals.

: http://publica.fraunhofer.de/documents/PX-40024.html