Strong-field extreme-ultraviolet dressing of atomic double excitation
Abstract
We report on the experimental observation of strong-field dressing of an autoionizing two-electron state in helium with intense extreme-ultraviolet laser pulses from a free-electron laser. The asymmetric Fano line shape of this transition is spectrally resolved, and we observe modifications of the resonance asymmetry structure for increasing free-electron-laser pulse energy on the order of few tens of J. A quantum-mechanical calculation of the time-dependent dipole response of this autoionizing state, driven by classical extreme-ultraviolet (XUV) electric fields, reveals a direct link between strong-field-induced energy and phase shifts of the doubly excited state and the Fano line-shape asymmetry. The experimental results obtained at the Free-Electron Laser in Hamburg (FLASH) thus correspond to transient energy shifts on the order of few meV, induced by strong XUV fields. These results open up a new way of performing non-perturbative XUV nonlinear optics for the light-matter interaction of resonant electronic transitions in atoms at short wavelengths.
Keywords
Cite
@article{arxiv.1907.06874,
title = {Strong-field extreme-ultraviolet dressing of atomic double excitation},
author = {Christian Ott and Lennart Aufleger and Thomas Ding and Marc Rebholz and Alexander Magunia and Maximilian Hartmann and Veit Stooß and David Wachs and Paul Birk and Gergana D Borisova and Kristina Meyer and Patrick Rupprecht and Carina da Costa Castanheira and Robert Moshammer and Andrew R Attar and Thomas Gaumnitz and Zhi Heng Loh and Stefan Düsterer and Rolf Treusch and Joachim Ullrich and Yuhai Jiang and Michael Meyer and Peter Lambropoulos and Thomas Pfeifer},
journal= {arXiv preprint arXiv:1907.06874},
year = {2019}
}
Comments
16 pages, 3 figures