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Optical Engineering • Open Access

Femtosecond laser-induced damage threshold of electron beam deposited dielectrics for 1-m class optics

Paper Abstract

In order to transport multi-petawatt (PW) femtosecond laser beams with large spectral bandwidth, specific mirrors have to be designed and manufactured. We report on an experimental study of the laser-damage resistance and other optical properties of coating materials deposited in a 1-m class coating chamber. The study is conducted on single-layer coatings deposited by electron beam evaporation at 500 fs. Based on the experience of large optics for nanosecond applications, hafnia and silica are particularly investigated. However, in the case of sub-15 fs, the spectral specifications for PW beam transport mirrors cannot be reached by classical high laser-resistant quarter-wave SiO2/HfO2 stacks. Therefore, we investigate the laser resistance of different dielectrics of interest deposited with electron-beam processes: Al2 O3, Y2O3, Sc2 O3, HfO2, Ta2 O5, TiO2. The influence of multiple pulse irradiations and environmental conditions, such as vacuum and temperature, is studied. With the investigation of multilayer stacks, we also show that there is no difference in behavior when a film is studied as a single layer or embedded in a stack. Based on these results, we were able to optimize high reflective (<99.5%), broadband (300 nm) and high laser-induced damage threshold (2.5  J/cm2) mirrors for PW applications.

Paper Details

Date Published: 30 June 2016
PDF: 8 pages
Opt. Eng. 56(1) 011001 doi: 10.1117/1.OE.56.1.011001
Published in: Optical Engineering Volume 56, Issue 1
Show Author Affiliations
Adrien Hervy, REOSC (France)
Aix Marseille Univ. (France)
Ecole Nationale Supérieure de Techniques Avancées (France)
Laurent Gallais, Aix Marseille Univ. (France)
Gilles Chériaux, Ecole Nationale Supérieure de Techniques Avancées (France)
Daniel Mouricaud, REOSC (France)

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