Mechanism of single-shot damage of Ru thin films irradiated by femtosecond extreme UV free-electron laser

0492824 - FZÚ 2019 RIV US eng J - Journal Article
Milov, I. - Makhotkin, I.A. - Sobierajski, R. - Medvedev, Nikita - Lipp, V. - Chalupský, Jaromír - Sturm, J.M. - Tiedtke, K. - de Vries, G. - Störmer, M. - Siewert, F. - van de Kruijs, R. - Louis, E. - Jacyna, I. - Jurek, M. - Juha, Libor - Hájková, Věra - Vozda, Vojtěch - Burian, Tomáš - Saksl, K. - Faatz, B. - Keitel, B. - Ploenjes, E. - Schreiber, S. - Toleikis, S. - Loch, R. - Hermann, M. - Strobel, S. - Nienhuys, H.-K. - Gwalt, G. - Mey, T. - Enkisch, H. - Bijkerk, F.
Mechanism of single-shot damage of Ru thin films irradiated by femtosecond extreme UV free-electron laser.
Optics Express. Roč. 26, č. 15 (2018), s. 19665-19685. ISSN 1094-4087
R&D Projects: GA ČR(CZ) GA17-05167s; GA MŠMT LG15013
Institutional support: RVO:68378271
Keywords : free-electron lasers * XUV mirrors * Ruthenium material * single-shot damage of thin films
OECD category: Optics (including laser optics and quantum optics)
Impact factor: 3.561, year: 2018

Ruthenium is a perspective material to be used for XUV mirrors at free-electron laser facilities. Yet, it is still poorly studied in the context of ultrafast laser-matter interaction. In this work, we present single-shot damage studies of thin Ru films irradiated by femtosecond XUV free-electron laser pulses at FLASH. Ex-situ analysis of the damaged spots, performed by different types of microscopy, shows that the weakest detected damage is surface roughening. For higher fluences we observe ablation of Ru. Combined simulations using Monte-Carlo code XCASCADE(3D) and the two-temperature model reveal that the damage mechanism is photomechanical spallation, similar to the case of irradiating the target with optical lasers. The analogy with the optical damage studies enables us to explain the observed damage morphologies.
Permanent Link: http://hdl.handle.net/11104/0286255