Ultrafast pump–probe experiments open the possibility to track fundamental material behaviour, such as changes in electronic configuration, in real time. To date, most of these experiments are performed using an electron or a high-energy photon beam that is synchronized to an infrared laser pulse. Entirely new opportunities can be explored if not only a single, but multiple synchronized, ultrashort, high-energy beams are used. However, this requires advanced radiation sources that are capable of producing dual-energy electron beams, for example. Here, we demonstrate simultaneous generation of twin-electron beams from a single compact laser wakefield accelerator. The energy of each beam can be individually adjusted over a wide range and our analysis shows that the bunch lengths and their delay inherently amount to femtoseconds. Our proof-of-concept results demonstrate an elegant way to perform multi-beam experiments in the future on a laboratory scale.

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This work was supported by DFG through the Cluster of Excellence Munich-Centre for Advanced Photonics (MAP EXC 158), DFG-Project Transregio TR-18 funding schemes, by EURATOM-IPP and the Max-Planck-Society. L.V. acknowledges the support by a grant from the Swedish Research Council (2016-05409). The authors thank F. Krausz for helpful comments. A.D. thanks I. Andriyash (WIS) for support with Chimera.

Author information

Author notes

    • J. Xu

    Present address: State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, China

  1. These authors contributed equally: J. Wenz, A. Döpp, K. Khrennikov.


  1. Ludwig-Maximilians-Universität München, Garching, Germany

    • J. Wenz
    • , A. Döpp
    • , K. Khrennikov
    • , S. Schindler
    • , M. F. Gilljohann
    • , H. Ding
    • , J. Götzfried
    • , A. Buck
    • , M. Heigoldt
    • , W. Helml
    •  & S. Karsch
  2. Max Planck Institut für Quantenoptik, Garching, Germany

    • J. Wenz
    • , A. Döpp
    • , K. Khrennikov
    • , S. Schindler
    • , M. F. Gilljohann
    • , H. Ding
    • , A. Buck
    • , J. Xu
    • , M. Heigoldt
    • , L. Veisz
    •  & S. Karsch
  3. Technische Universität Dortmund, Dortmund, Germany

    • W. Helml
  4. Technische Universität München, Garching, Germany

    • W. Helml
  5. Department of Physics, Umea University, Umea, Sweden

    • L. Veisz


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A.B., M.H., K.K., J.W., J.X., L.V. and S.K. performed the experiments with ATLAS-60 at the MPQ. A.D., H.D., M.F.G., J.G., S.S. and S.K. performed the experiments with the upgraded laser system at LEX Photonics. A.D., K.K., S.S. and J.W. analysed the experimental data. A.D. performed PIC simulations, radiation and beam transport calculations. A.D., W.H., K.K., J.W., L.V. and S.K. discussed the results. A.D., K.K. and J.W. wrote the paper. S.K. supervised the project.

Competing interests

The authors declare no competing interests.

Corresponding authors

Correspondence to A. Döpp or S. Karsch.

Supplementary information

  1. Supplementary Information

    Further experimental data as well as discussions about electron bunch delay, possible applications and beam transport.

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