TY  - JOUR
AU  - Ding, Thomas
AU  - Rebholz, Marc
AU  - Aufleger, Lennart
AU  - Hartmann, Maximilian
AU  - Stooß, Veit
AU  - Magunia, Alexander
AU  - Birk, Paul
AU  - Borisova, Gergana Dimitrova
AU  - Wachs, David
AU  - da Costa Castanheira, Carina
AU  - Rupprecht, Patrick
AU  - Mi, Yonghao
AU  - Attar, Andrew R.
AU  - Gaumnitz, Thomas
AU  - Loh, Zhi-Heng
AU  - Roling, Sebastian
AU  - Butz, Marco
AU  - Zacharias, Helmut
AU  - Duesterer, Stefan
AU  - Treusch, Rolf
AU  - Eislage, Arvid
AU  - Cavaletto, Stefano M.
AU  - Ott, Christian
AU  - Pfeifer, Thomas
TI  - Measuring the frequency chirp of extreme-ultraviolet free-electron laser pulses by transient absorption spectroscopy
JO  - Nature Communications
VL  - 12
IS  - 1
SN  - 2041-1723
CY  - [London]
PB  - Nature Publishing Group UK
M1  - PUBDB-2021-00854
SP  - 643 (1-7)
PY  - 2021
AB  - High-intensity ultrashort pulses at extreme ultraviolet (XUV) and x-ray photon energies, delivered by  state-of-the-art free-electron lasers (FELs), are revolutionizing the field of ultrafast spectroscopy. For crossing the next frontiers of research, precise, reliable and practical photonic tools for the spectro-temporal characterization of the pulses are becoming steadily more important. Here, we experimentally demonstrate a technique for the direct measurement of the frequency chirp of extreme-ultraviolet free-electron laser pulses based on fundamental nonlinear optics. It is implemented in XUV-only pump-probe transient-absorption geometry and provides in-situ information on the time-energy structure of FEL pulses. Using a rate-equation model for the time-dependent absorbance changes of anionized neon target, we show how the frequency chirp can be directly extracted and quantified from measured data. Since the method does not rely on an additional external field, we expect a widespread implementation at FELs benefiting multiple science fields by in-situ on-target measurement and optimization of FEL-pulse properties.
LB  - PUB:(DE-HGF)16
C6  - pmid:33510142
UR  - <Go to ISI:>//WOS:000616784300004
DO  - DOI:10.1038/s41467-020-20846-1
UR  - https://bib-pubdb1.desy.de/record/454947
ER  -