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Coherent optical vortices from relativistic electron beams

Nature Physics volume 9, pages 549553 (2013) | Download Citation

Abstract

Recent advances in the production and control of high-brightness electron beams (e-beams) have enabled a new class of intense light sources based on the free electron laser (FEL) that can examine matter at ångstrom length and femtosecond time scales1. The free, or unbound, electrons act as the lasing medium, which provides unique opportunities to exquisitely control the spatial and temporal structure of the emitted light through precision manipulation of the electron distribution. We present an experimental demonstration of light with orbital angular momentum (OAM; ref. 2) generated from a relativistic e-beam rearranged into an optical scale helix by a laser. With this technique, we show that a Gaussian laser mode can be effectively up-converted to an OAM mode in an FEL using only the e-beam as a mode-converter. Results confirm theoretical predictions3,4, and pave the way for the production of coherent OAM light with unprecedented brightness down to hard X-ray wavelengths for wide ranging applications in modern light sources.

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References

  1. 1.

    & X-ray free-electron lasers. Nature Photon. 4, 814–821 (2010).

  2. 2.

    , , & Orbital angular momentum of light and the transformation of Laguerre-Gaussian laser modes. Phys. Rev. A 45, 8185–8189 (1992).

  3. 3.

    et al. Helical electron-beam microbunching by harmonic coupling in a helical undulator. Phys. Rev. Lett. 102, 174801 (2009).

  4. 4.

    , & Generating optical orbital angular momentum in a high-gain free-electron laser at the first harmonic. Phys. Rev. Lett. 106, 164803 (2011).

  5. 5.

    , & Structured Light and Its Applications: An Introduction to Phase-Structured Beams and Nanoscale Optical Forces 1st edn (Academic, 2008).

  6. 6.

    , , & Direct observation of transfer of angular momentum to absorptive particles from a laser beam with a phase singularity. Phys. Rev. Lett. 75, 826–829 (1995).

  7. 7.

    , , & Shadow effects in spiral phase contrast microscopy. Phys. Rev. Lett. 94, 233902 (2005).

  8. 8.

    et al. Holographic ghost imaging and the violation of a Bell inequality. Phys. Rev. Lett. 103, 083602 (2009).

  9. 9.

    & Optical pumping of orbital angular momentum of light in cold cesium atoms. Phys. Rev. Lett. 83, 4967–4970 (1999).

  10. 10.

    et al. Quantum entanglement of high angular momenta. Science 338, 640–643 (2012).

  11. 11.

    et al. Terabit free-space data transmission employing orbital angular momentum multiplexing. Nature Photon. 6, 488–496 (2012).

  12. 12.

    , , & X-ray circular dichroism as a probe of orbital magnetization. Phys. Rev. Lett. 68, 1943–1946 (1992).

  13. 13.

    & Prediction of strong dichroism induced by X rays carrying orbital momentum. Phys. Rev. Lett. 98, 157401 (2007).

  14. 14.

    , , & Astigmatic laser mode converters and transfer of orbital angular momentum. Opt. Commun. 96, 123–132 (1993).

  15. 15.

    , , , & Laser beams with phase singularities. Opt. Quant. Electron. 24, S951–S962 (1992).

  16. 16.

    et al. Integrated compact optical vortex beam emitters. Science 338, 363–366 (2012).

  17. 17.

    , , & Helical-wavefront laser beams produced with a spiral phaseplate. Opt. Commun. 112, 327–327 (1994).

  18. 18.

    , & Laser-beams with screw dislocations in their wave-fronts. JETP Lett. 52, 429–431 (1990).

  19. 19.

    et al. Observation of an X-ray vortex. Opt. Lett. 27, 1752–1754 (2002).

  20. 20.

    et al. Bragg X-ray ptychography of a silicon crystal: Visualization of the dislocation strain field and the production of a vortex beam. Phys. Rev. B 87, 121201 (2013).

  21. 21.

    & Generation of high-energy photons with large orbital angular momentum by Compton backscattering. Phys. Rev. Lett. 106, 013001 (2011).

  22. 22.

    & Proposal for generating brilliant X-ray beams carrying orbital angular momentum. Phys. Rev. Lett. 100, 124801 (2008).

  23. 23.

    et al. Experimental observation of helical microbunching of a relativistic electron beam. Appl. Phys. Lett. 100, 091110 (2012).

  24. 24.

    et al. Demonstration of the echo-enabled harmonic generation technique for short-wavelength seeded free electron lasers. Phys. Rev. Lett. 105, 114801 (2010).

  25. 25.

    et al. Evidence of high harmonics from echo-enabled harmonic generation for seeding X-ray free electron lasers. Phys. Rev. Lett. 108, 024802 (2012).

  26. 26.

    et al. Single-shot coherent diffraction imaging of microbunched relativistic electron beams for free-electron laser applications. Phys. Rev. Lett. 110, 094802 (2013).

  27. 27.

    & Phase retrieval from series of images obtained by defocus variation. Opt. Commun. 199, 65–75 (2001).

  28. 28.

    , & Single-slit diffraction of an optical beam with phase singularity. Opt. Lasers Eng. 47, 123–126 (2009).

  29. 29.

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

  30. 30.

    & Echo-enabled X-ray vortex generation. Phys. Rev. Lett. 109, 224801 (2012).

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Acknowledgements

The authors would like to acknowledge funding supported by US DOE under Contract Nos. DE-AC02-76SF00515 and DE-FG02-07ER46272.

Author information

Affiliations

  1. SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA

    • Erik Hemsing
    • , Michael Dunning
    • , Dao Xiang
    • , Agostino Marinelli
    •  & Carsten Hast
  2. Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095, USA

    • Andrey Knyazik
    •  & James B. Rosenzweig

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Contributions

E.H. conceived the theoretical concept and designed the experimental technique. E.H., A.K. and M.D. carried out the experiment. A.K. designed and built the helical undulator. A.M. contributed to the theoretical work and data analysis. D.X., J.B.R. and C.H. provided guidance on the experiment and on potential applications. All authors contributed to writing the paper.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Erik Hemsing.

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DOI

https://doi.org/10.1038/nphys2712

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