Large area ion beam sputtered dielectric ultrafast mirrors for petawatt laser beamlines
Thomas Willemsen, Uddhab Chaulagain, Irena Havlíčková, S. Borneis, Wolfgang Ebert, Henrik Ehlers, M. Gauch, Tobias Groß, Daniel Kramer, T. Laštovička, J. Nejdl, B. Rus, Konrad Schrader, Tomas Tolenis, František Vaněk, Praveen Kumar Velpula, S. Weber
Abstract
The latest advances in petawatt laser technology within the ELI Beamlines project have stimulated the development of large surface area dielectrically coated mirrors meeting all demanding requirements for guiding the compressed 30 J, 25 fs HAPLS laser beam at 10 Hz repetition rate and a center wavelength of 810 nm entirely in vacuum. We describe the production and evaluation of Ta 2 O 5 /HfO 2 /SiO 2 ion beam sputtered coated (440 × 290 × 75) mm 3 beam transport mirrors. No crazing was observed after thirty vacuum-air cycles. A laser induced damage threshold of 0.76 J/cm 2 (fluence on mirror surface) was achieved and maintained at high shot rates.