Volume 228, 2021

XUV pump–XUV probe transient absorption spectroscopy at FELs


The emergence of ultra-intense extreme-ultraviolet (XUV) and X-ray free-electron lasers (FELs) has opened the door for the experimental realization of non-linear XUV and X-ray spectroscopy techniques. Here we demonstrate an experimental setup for an all-XUV transient absorption spectroscopy method for gas-phase targets at the FEL. The setup combines a high spectral resolving power of EE ≈ 1500 with sub-femtosecond interferometric resolution, and covers a broad XUV photon-energy range between approximately 20 and 110 eV. We demonstrate the feasibility of this setup firstly on a neon target. Here, we intensity- and time-resolve key aspects of non-linear XUV-FEL light–matter interactions, namely the non-resonant ionization dynamics and resonant coupling dynamics of bound states, including XUV-induced Stark shifts of energy levels. Secondly, we show that this setup is capable of tracking the XUV-initiated dissociation dynamics of small molecular targets (oxygen and diiodomethane) with site-specific resolution, by measuring the XUV transient absorption spectrum. In general, benefitting from a single-shot detection capability, we show that the setup and method provides single-shot phase-locked XUV pulse pairs. This lays the foundation to perform, in the future, experiments as a function of the XUV interferometric time delay and the relative phase, which enables advanced coherent non-linear spectroscopy schemes in the XUV and X-ray spectral range.

Graphical abstract: XUV pump–XUV probe transient absorption spectroscopy at FELs

Associated articles

Article information

Article type
15 Sep 2020
05 Nov 2020
First published
07 Nov 2020
This article is Open Access
Creative Commons BY license

Faraday Discuss., 2021,228, 519-536

XUV pump–XUV probe transient absorption spectroscopy at FELs

T. Ding, M. Rebholz, L. Aufleger, M. Hartmann, V. Stooß, A. Magunia, P. Birk, G. D. Borisova, C. da Costa Castanheira, P. Rupprecht, Y. Mi, T. Gaumnitz, Z. Loh, S. Roling, M. Butz, H. Zacharias, S. Düsterer, R. Treusch, C. Ott and T. Pfeifer, Faraday Discuss., 2021, 228, 519 DOI: 10.1039/D0FD00107D

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