Highly nonlinear ionization of atoms induced by intense high-harmonic pulses

Björn Senfftleben; Martin Kretschmar; Andreas Hoffmann; Mario Sauppe; Johannes Tümmler; Ingo Will; Tamás Nagy; Marc J. J. Vrakking; Daniela Rupp; Bernd Schütte

arXiv · 1911.01375

Highly nonlinear ionization of atoms induced by intense high-harmonic pulses

Björn Senfftleben·Martin Kretschmar·Andreas Hoffmann·Mario Sauppe·Johannes Tümmler·Ingo Will·Tamás Nagy·Marc J. J. Vrakking·Daniela Rupp·Bernd Schütte

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Abstract

Intense extreme-ultraviolet (XUV) pulses enable the investigation of XUV-induced nonlinear processes and are a prerequisite for the development of attosecond pump - attosecond probe experiments. While highly nonlinear processes in the XUV range have been studied at free-electron lasers (FELs), high-harmonic generation (HHG) has allowed the investigation of low-order nonlinear processes. Here we suggest a concept to optimize the HHG intensity, which surprisingly requires a scaling of the experimental parameters that differs substantially from optimizing the HHG pulse energy. As a result, we are able to study highly nonlinear processes in the XUV range using a driving laser with a modest ($\approx 10$ mJ) pulse energy. We demonstrate our approach by ionizing Ar atoms up to Ar$^{5+}$, requiring the absorption of at least 10 XUV photons.

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Björn Senfftleben, Martin Kretschmar, Andreas Hoffmann, Mario Sauppe, Johannes Tümmler, Ingo Will, Tamás Nagy, Marc J. J. Vrakking, Daniela Rupp, Bernd Schütte. 2019-11-04. Highly nonlinear ionization of atoms induced by intense high-harmonic pulses. https://arxiv.org/abs/1911.01375

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