Laser-driven high-flux source of coherent quasi-monochromatic extreme ultraviolet radiation for coincidence spectroscopy

Julian Späthe; Sebastian Hell; Martin Wünsche; Robert Klas; Jan Rothhardt; Jens Limpert; Thomas Siefke; Gerhard G Paulus; Matthias Kübel

arXiv · 2507.02561

Laser-driven high-flux source of coherent quasi-monochromatic extreme ultraviolet radiation for coincidence spectroscopy

Julian Späthe·Sebastian Hell·Martin Wünsche·Robert Klas·Jan Rothhardt·Jens Limpert·Thomas Siefke·Gerhard G Paulus·Matthias Kübel

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Abstract

We present a source of coherent extreme ultraviolet (XUV) radiation with a flux of 10$^{13}$ photons per second at 26.5 eV. The source is based on high-harmonic generation (HHG) in argon and pumped by a frequency-doubled 100 kHz repetition rate fiber laser providing 30 fs pulses centered at 515 nm. We report on the characterization of the source and the generated XUV radiation using optical imaging and photoelectron spectroscopy. The generated radiation is quasi-monochromatized using a suitably coated XUV mirror and used for coincidence spectroscopy of ions and electrons generated from a cold gas target. The high intensity of the focused XUV pulses is confirmed by the observation of two-photon double ionization in argon. Moreover, we demonstrate the capability to perform pump-probe experiments using XUV and visible laser pulses.

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Julian Späthe, Sebastian Hell, Martin Wünsche, Robert Klas, Jan Rothhardt, Jens Limpert, Thomas Siefke, Gerhard G Paulus, Matthias Kübel. 2025-07-03. Laser-driven high-flux source of coherent quasi-monochromatic extreme ultraviolet radiation for coincidence spectroscopy. https://arxiv.org/abs/2507.02561

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