Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Fresh-slice multicolour X-ray free-electron lasers


X-ray free-electron lasers (XFELs) provide femtosecond X-ray pulses with a narrow energy bandwidth and unprecedented brightness. Ultrafast physical and chemical dynamics, initiated with a site-specific X-ray pulse, can be explored using XFELs with a second ultrashort X-ray probe pulse. However, existing double-pulse schemes are complicated, difficult to customize or provide only low-intensity pulses. Here we present the novel fresh-slice technique for multicolour pulse production, wherein different temporal slices of an electron bunch lase to saturation in separate undulator sections. This method combines electron bunch tailoring from a passive wakefield device with trajectory control to provide multicolour pulses. The fresh-slice scheme outperforms existing techniques at soft X-ray wavelengths. It produces femtosecond pulses with a power of tens of gigawatts and flexible colour separation. The pulse delay can be varied from temporal overlap to almost one picosecond. We also demonstrate the first three-colour XFEL and variably polarized two-colour pulses.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: Fresh-slice multipulse scheme.
Figure 2: Fresh-slice two-colour single shots at 707 eV.
Figure 3: Demonstration of the fresh-slice two-colour FEL at 640 eV.
Figure 4: Polarization control of the probe pulse.
Figure 5: Demonstration of the fresh-slice three-colour XFEL at 780 eV.


  1. 1

    Nilsson, A. & Pettersson, L. G. M. The structural origin of anomalous properties of liquid water. Nat. Commun. 6, 8998 (2015).

    ADS  Article  Google Scholar 

  2. 2

    Chen, C. T. et al. Experimental confirmation of the X-ray magnetic circular dichroism sum rules for iron and cobalt. Phys. Rev. Lett. 75, 152–155 (1995).

    ADS  Article  Google Scholar 

  3. 3

    Luo, K. et al. Charge-compensation in 3D-transition-metal-oxide intercalation cathodes through the generation of localized electron holes on oxygen. Nat. Chem. 8, 684–691 (2016).

    Article  Google Scholar 

  4. 4

    Begley, R. F., Harvey, A. B. & Byer, R. L. Coherent anti-stokes Raman spectroscopy. Appl. Phys. Lett. 25, 387–390 (1974).

    ADS  Article  Google Scholar 

  5. 5

    Schenk, M. & Kiefer, W. Resonance coherent anti-stokes Raman spectroscopy of iodine in solution. J. Chem. Phys. 105, 2177–2187 (1996).

    ADS  Article  Google Scholar 

  6. 6

    Zheng, J. et al. Ultrafast dynamics of solute-solvent complexation observed at thermal equilibrium in real time. Science 309, 1338–1343 (2005).

    ADS  Article  Google Scholar 

  7. 7

    Park, S., Kwak, K. & Fayer, M. D. Ultrafast 2D-IR vibrational echo spectroscopy: a probe of molecular dynamics. Laser Phys. Lett. 4, 704–718 (2007).

    ADS  Article  Google Scholar 

  8. 8

    Rosenfeld, D. E., Gengeliczki, Z., Smith, B. J., Stack, T. D. P. & Fayer, M. D. Structural dynamics of a catalytic monolayer probed by ultrafast 2D IR vibrational echoes. Science 334, 634–639 (2011).

    ADS  Article  Google Scholar 

  9. 9

    Berrah, N. & Bucksbaum, P. The ultimate X-ray machine. Sci. Am. 24, 54–61 (2015).

    Article  Google Scholar 

  10. 10

    Bucksbaum, P. & Berrah, N. Brighter and faster: the promise and challenge of the X-ray free-electron laser. Phys. Today 68, 26–32 (2015).

    Article  Google Scholar 

  11. 11

    Emma, P. et al. First lasing and operation of an angstrom-wavelength free-electron laser. Nat. Photon. 4, 641–647 (2009).

    ADS  Article  Google Scholar 

  12. 12

    Ishikawa, T. et al. A compact X-ray free-electron laser emitting in the sub-angstrom region. Nat. Photon. 6, 540–544 (2012).

    ADS  Article  Google Scholar 

  13. 13

    Allaria, E. et al. Two-stage seeded soft-X-ray free-electron laser. Nat. Photon. 7, 913–918 (2013).

    ADS  Article  Google Scholar 

  14. 14

    Ackermann, W. et al. Operation of a free-electron laser from the extreme ultraviolet to the water window. Nat. Photon. 1, 336–342 (2007).

    ADS  Article  Google Scholar 

  15. 15

    Doumy, G. et al. Nonlinear atomic response to intense ultrashort X rays. Phys. Rev. Lett. 106, 083002 (2011).

    ADS  Article  Google Scholar 

  16. 16

    Berrah, N. et al. Double-core-hole spectroscopy for chemical analysis with an intense X-ray femtosecond laser. Proc. Natl Acad. Sci. USA 108, 16912–16915 (2011).

    ADS  Article  Google Scholar 

  17. 17

    Erk, B. et al. Imaging charge transfer in iodomethane upon X-ray photoabsorption. Science 345, 288–291 (2014).

    ADS  Article  Google Scholar 

  18. 18

    Lutman, A. A. et al. Experimental demonstration of femtosecond two-color X-ray free-electron lasers. Phys. Rev. Lett. 110, 134801 (2013).

    ADS  Article  Google Scholar 

  19. 19

    Hara, T. et al. Two-colour hard X-ray free-electron laser with wide tunability. Nat. Commun. 4, 2919 (2013).

    ADS  Article  Google Scholar 

  20. 20

    Marinelli, A. et al. High-intensity double-pulse X-ray free-electron laser. Nat. Commun. 6, 6369 (2015).

    ADS  Article  Google Scholar 

  21. 21

    Allaria, E. et al. Two-colour pump-probe experiments with a twin-pulse-seed extreme ultraviolet free-electron laser. Nat. Commun. 4, 2476 (2013).

    ADS  Article  Google Scholar 

  22. 22

    Ferrari, E. et al. Widely tunable two-colour seeded free-electron laser source for resonant-pump resonant-probe magnetic scattering. Nat. Commun. 7, 10343 (2016).

    ADS  Article  Google Scholar 

  23. 23

    Lutman, A. A. et al. Demonstration of single-crystal self-seeded two-color X-ray free-electron lasers. Phys. Rev. Lett. 113, 254801 (2014).

    ADS  Article  Google Scholar 

  24. 24

    Prince, K. et al. Coherent control with a short-wavelength free-electron laser. Nat. Photon. 10, 176–179 (2016).

    ADS  Article  Google Scholar 

  25. 25

    Lutman, A. A. et al. Polarization control in an X-ray free-electron laser. Nat. Photon. 10, 468–472 (2016).

    ADS  Article  Google Scholar 

  26. 26

    Prat, E., Löhl, F. & Reiche, S. Efficient generation of short and high-power X-ray free-electron-laser pulses based on superradiance with a transversely tilted beam. Phys. Rev. ST Accel. Beams 18, 100701 (2015).

    ADS  Article  Google Scholar 

  27. 27

    Prat, E., Calvi, M. & Reiche, S. Generation of ultra-large-bandwidth X-ray free-electron-laser pulses with a transverse-gradient undulator. J. Synchrotron Radiat. 23, 874–879 (2016).

    Article  Google Scholar 

  28. 28

    Reiche, S. & Prat, E. Two-color operation of a free-electron laser with a tilted beam. J. Synchrotron Radiat. 23, 869–873 (2016).

    Article  Google Scholar 

  29. 29

    Bane, K. & Stupakov, G. Corrugated pipe as a beam dechirper. Nucl. Instrum. Methods Phys. Res. A 690, 106–110 (2012).

    ADS  Article  Google Scholar 

  30. 30

    Zhang, Z. et al. Electron beam energy chirp control with a rectangular corrugated structure at the Linac Coherent Light Source. Phys. Rev. ST Accel. Beams 18, 010702 (2015).

    ADS  Article  Google Scholar 

  31. 31

    Antipov, S. et al. Experimental demonstration of energy-chirp compensation by a tunable dielectric-based structure. Phys. Rev. Lett. 112, 114801 (2014).

    ADS  Article  Google Scholar 

  32. 32

    Emma, P. et al. Experimental demonstration of energy-chirp control in relativistic electron bunches using a corrugated pipe. Phys. Rev. Lett. 112, 034801 (2014).

    ADS  Article  Google Scholar 

  33. 33

    Deng, H. et al. Experimental demonstration of longitudinal beam phase-space linearizer in a free-electron laser facility by corrugated structures. Phys. Rev. Lett. 113, 254802 (2014).

    ADS  Article  Google Scholar 

  34. 34

    Fu, F. et al. Demonstration of nonlinear-energy-spread compensation in relativistic electron bunches with corrugated structures. Phys. Rev. Lett. 114, 114801 (2015).

    ADS  Article  Google Scholar 

  35. 35

    Guetg, M. W. et al. Commissioning of the RadiaBeam/SLAC dechirper. In Proc. 7th International Particle Accelerator Conf. 809–812 (JACoW, 2016).

  36. 36

    Bane, K., Stupakov, G. & Zagorodnov, I. Analytical formulas for short bunch wakes in a flat dechirper. Phys. Rev. ST Accel. Beams 19, 084401 (2016).

    ADS  Article  Google Scholar 

  37. 37

    Bane, K. & Stupakov, G. Dechirper wakefields for short bunches. Nucl. Instrum. Methods Phys. Res. A 820, 156–163 (2016).

    ADS  Article  Google Scholar 

  38. 38

    Novokhatski, A. Wakefield potentials of corrugated structures. Phys. Rev. ST Accel. Beams 18, 104402 (2015).

    ADS  Article  Google Scholar 

  39. 39

    Nuhn, H.-D., Marks, S. & Wu, J. LCLS-II Undulator Tolerance Analysis SLAC-109 PUB-15062 (US Department of Energy, 2012).

    Google Scholar 

  40. 40

    Emma, P. et al. Femtosecond and subfemtosecond X-ray pulses from a self-amplified spontaneous-emission-based free-electron laser. Phys. Rev. Lett. 92, 074801 (2004).

    ADS  Article  Google Scholar 

  41. 41

    Ding, Y. et al. Generating femtosecond X-ray pulses using an emittance-spoiling foil in free-electron lasers. Appl. Phys. Lett. 107, 191104 (2015).

    ADS  Article  Google Scholar 

  42. 42

    Marinelli, A. et al. Optical shaping of X-ray free-electron lasers. Phys. Rev. Lett. 116, 254801 (2016).

    ADS  Article  Google Scholar 

  43. 43

    Marinelli, A. et al. Multicolor operation and spectral control in a gain-modulated X-ray free-electron laser. Phys. Rev. Lett. 111, 134801 (2013).

    ADS  Article  Google Scholar 

  44. 44

    Ratner, D. et al. Experimental demonstration of a soft X-ray self-seeded free-electron laser. Phys. Rev. Lett. 114, 054801 (2015).

    ADS  Article  Google Scholar 

  45. 45

    Amman, J. et al. Demonstration of self-seeding in a hard-X-ray free-electron laser. Nat. Photon. 6, 693–698 (2012).

    ADS  Article  Google Scholar 

  46. 46

    Behrens, C. et al. Few-femtosecond time-resolved measurements of X-ray free-electron lasers. Nat. Commun. 5, 4762 (2014).

    Article  Google Scholar 

  47. 47

    Bettoni, S., Craievich, P., Lutman, A. A. & Pedrozzi, M. Temporal profile measurements of relativistic electron bunch based on wakefield generation. Phys. Rev. Accel. Beams 19, 021304 (2016).

    ADS  Article  Google Scholar 

  48. 48

    Emma, C. et al. High efficiency, high brightness X-ray free electron lasers via fresh bunch self-seeding. In Proc. 7th International Particle Accelerator Conf. 805–808 (JACoW, 2016).

Download references


We thank K. Bane and R. Iverson for useful discussions and support. This work was supported by Department of Energy contract nos DE-AC02-76SF00515 and DE-SC0012376.

Author information




A.A.L., J.P.M and R.N.C co-wrote the manuscript with input from all co-authors. A.A.L conceived the fresh-slice schemes with the dechirper. A.A.L., T.J.M., J.P.M., M.W.G., N.B., R.N.C., Y.D., Z.H., A.M., S.M. and J.C.U.Z. participated in the experiments.

Corresponding author

Correspondence to Alberto A. Lutman.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Lutman, A., Maxwell, T., MacArthur, J. et al. Fresh-slice multicolour X-ray free-electron lasers. Nature Photon 10, 745–750 (2016).

Download citation

Further reading


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing