FisMat2017 - Submission - View

Abstract's title: Long-living non-thermal electron distribution in aluminum excited by femtosecond extreme-ultraviolet radiation
Submitting author: Francesco Bisio
Affiliation: CNR-SPIN
Affiliation Address: Corso perrone 24, 16152, Genova, Italy
Country: Italy
Oral presentation/Poster (Author's request): Oral presentation
Other authors and affiliations: Emiliano Principi (Elettra-Sincrotrone Trieste S. C. p. A., Strada Statale 14, km 163.5, 34149 Basovizza, Italy), Michele Magnozzi, (OptMatLab, Dipartimento di Fisica, Universit\`{a} di Genova, via Dodecaneso 33, I-16146 Genova, Italy), Alberto Simoncig (Elettra-Sincrotrone Trieste S. C. p. A., Strada Statale 14, km 163.5, 34149 Basovizza, Italy), Erika Giangrisostomi (Elettra-Sincrotrone Trieste S. C. p. A., Strada Statale 14, km 163.5, 34149 Basovizza, Italy), Riccardo Mincigrucci (Elettra-Sincrotrone Trieste S. C. p. A., Strada Statale 14, km 163.5, 34149 Basovizza, Italy), Luca Pasquali (Dipartimento di Ingegneria "Enzo Ferrari", Università di Modena e Reggio Emilia, Via Vivarelli 10, 41125 Modena, Italy), Claudio Masciovecchio (Elettra-Sincrotrone Trieste S. C. p. A., Strada Statale 14, km 163.5, 34149 Basovizza, Italy), Federico Boscherini (Dipartimento di Fisica e Astronomia, Università di Bologna, Viale C. Berti Pichat 6/2, 40127, Bologna, Italy), Maurizio Canepa (OptMatLab, Dipartimento di Fisica, Universit\ à di Genova, via Dodecaneso 33, I-16146 Genova, Italy)
Abstract

We report a time-resolved study of the relaxation dynamics of Al films excited by ultrashort intense free-electron laser (FEL) extreme-ultraviolet pulses. The system response was measured through a pump-probe detection scheme, in which an intense FEL pulse

tuned around the Al L2,3 edge (72.5 eV) acted as the pump, while a time-delayed ultrafast pulse probed the near-infrared (NIR) reflectivity of the Al film. Remarkably, following the intense FEL excitation, the reflectivity of the film exhibited no detectable variation for hundreds of fs.

Following this latency time, sizable reflectivity changes were observed.

Exploiting recent theoretical calculations of the EUV-excited electron dynamics [N. Medvedev  et al., Phys. Rev. Lett. 107 165003 (2011)], the delayed NIR-reflectivity evolution is interpreted invoking the formation of very-long-living non-thermal hot electron distributions in Al after exposure to intense EUV pulses. Our data represent the first evidence in the time domain of such an intriguing behaviour.