Freiburg 2024 – scientific programme

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A: Fachverband Atomphysik

A 33: Poster VI

A 33.29: Poster

Thursday, March 14, 2024, 17:00–19:00, Tent A

Tracking XUV strong couplings with absorption line-shape changes and underlying population transfer with a convolutional neural network — •Alexander Magunia, Daniel Richter, Marc Rebholz, Christian Ott, and Thomas Pfeifer — Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany

The electronic states within an atom or molecule determine their properties, also while interacting with their environment. As shown recently in helium atoms, electronic population can be effectively transferred from the ground state to valence states with intense extreme-ultraviolet (XUV) free-electron laser pulses via Rabi cycling (1). The underlying strong-field coupling of states during the Rabi dynamics also leads to changes in the absorption line shape (2,3).

In our contribution, we will describe methods to model and understand ultrafast strong couplings in a two-level system and resulting absorption line-shape changes. Furthermore, we extend the system by including two excited bound states or an ionization continuum. We also present a convolutional neural network, which can predict time-resolved electronic bound-state populations from the (simulated) absorption spectra.

(1) S.N. et al., Nature 608, 488-493 (2022)

(2) Phys. Rev. Lett. 123, 163201 (2019)

(3) Appl. Sci. 10, (18) 6153 (2020)

Keywords: free-electron laser; absorption line shape; convolutional neural network; electron population dynamics