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.

Acceleration of neutral atoms in strong short-pulse laser fields


A charged particle exposed to an oscillating electric field experiences a force proportional to the cycle-averaged intensity gradient. This so-called ponderomotive force1 plays a major part in a variety of physical situations such as Paul traps2,3 for charged particles, electron diffraction in strong (standing) laser fields4,5,6 (the Kapitza–Dirac effect) and laser-based particle acceleration7,8,9. Comparably weak forces on neutral atoms in inhomogeneous light fields may arise from the dynamical polarization of an atom10,11,12; these are physically similar to the cycle-averaged forces. Here we observe previously unconsidered extremely strong kinematic forces on neutral atoms in short-pulse laser fields. We identify the ponderomotive force on electrons as the driving mechanism, leading to ultrastrong acceleration of neutral atoms with a magnitude as high as 1014 times the Earth’s gravitational acceleration, g. To our knowledge, this is by far the highest observed acceleration on neutral atoms in external fields and may lead to new applications in both fundamental and applied physics.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Rent or buy this article

Get just this article for as long as you need it


Prices may be subject to local taxes which are calculated during checkout

Figure 1: Deflection of neutral He atoms after interaction with a focused laser beam.
Figure 2: Maximum velocity vmax(z ) gained by neutral He atoms.
Figure 3: Maximum velocity v max (0) transferred to He and Ne at the focal plane as a function of the laser pulse duration at constant laser intensity.


  1. Kibble, T. W. B. Refraction of electron beams by intense electromagnetic waves. Phys. Rev. Lett. 16, 1054–1056 (1966)

    Article  CAS  ADS  Google Scholar 

  2. Boot, H. A. H. &. Harvie, R. B. R.-S. Charged particles in a non-uniform radio-frequency field. Nature 180, 1187 (1957)

    Article  ADS  Google Scholar 

  3. Dehmelt, H. G. Radio-frequency spectroscopy of stored ions. Adv. At. Mol. Phys. 3, 53–72 (1967)

    Article  CAS  ADS  Google Scholar 

  4. Kapitza, P. & Dirac, P. The reflection of electrons from standing light waves. Proc. Camb. Philos. Soc. 29, 297–300 (1933)

    Article  ADS  Google Scholar 

  5. Bucksbaum, P. H., Schumacher, D. W. & Bashkansky, M. High-intensity Kapitza-Dirac effect. Phys. Rev. Lett. 61, 1182–1185 (1988)

    Article  CAS  ADS  Google Scholar 

  6. Freimund, D. L., Aflatooni, K. & Batelaan, H. Observation of the Kapitza-Dirac effect. Nature 413, 142–143 (2001)

    Article  CAS  ADS  Google Scholar 

  7. Tajima, T. & Dawson, J. M. Laser electron accelerator. Phys. Rev. Lett. 43, 267–270 (1979)

    Article  CAS  ADS  Google Scholar 

  8. Geddes, C. et al. High-quality electron beams from a laser wakefield accelerator using plasma-channel guiding. Nature 431, 538–541 (2004)

    Article  CAS  ADS  Google Scholar 

  9. Mourou, G., Tajima, T. & Bulanov, S. Optics in the relativistic regime. Rev. Mod. Phys. 78, 309–371 (2006)

    Article  CAS  ADS  Google Scholar 

  10. Gould, P. L., Ruff, G. A. & Pritchard, D. E. Diffraction of atoms by light: The near-resonant Kapitza-Dirac effect. Phys. Rev. Lett. 56, 827–830 (1986)

    Article  CAS  ADS  Google Scholar 

  11. Chu, S., Bjorkholm, J. E., Ashkin, A. & Cable, A. Experimental observation of optically trapped atoms. Phys. Rev. Lett. 57, 314–317 (1986)

    Article  CAS  ADS  Google Scholar 

  12. Grimm, R., Weidemüller, M. & Ovchinnikov, Y. Optical dipole traps for neutral atoms. Adv. At. Mol. Phys. 42, 95–170 (2000)

    Article  CAS  ADS  Google Scholar 

  13. de Boer, M. P. & Muller, H. G. Observation of large populations in excited states after short-pulse multiphoton ionization. Phys. Rev. Lett. 68, 2747–2750 (1992)

    Article  CAS  ADS  Google Scholar 

  14. Nubbemeyer, T., Gorling, K., Saenz, A., Eichmann, U. & Sandner, W. Strong-field tunneling without ionization. Phys. Rev. Lett. 101, 233001 (2008)

    Article  CAS  ADS  Google Scholar 

  15. Corkum, P. B. Plasma perspective on strong field multiphoton ionization. Phys. Rev. Lett. 71, 1994–1997 (1993)

    Article  CAS  ADS  Google Scholar 

  16. Krapchev, V. B. Kinetic theory of the ponderomotive effects in a plasma. Phys. Rev. Lett. 42, 497–500 (1979)

    Article  CAS  ADS  Google Scholar 

  17. McNaught, S. J., Knauer, J. P. & Meyerhofer, D. D. Photoelectron initial conditions for tunneling ionization in a linearly polarized laser. Phys. Rev. A 58, 1399–1411 (1998)

    Article  CAS  ADS  Google Scholar 

  18. Wells, E., Ben-Itzhak, I. & Jones, R. R. Ionization of atoms by the spatial gradient of the pondermotive potential in a focused laser beam. Phys. Rev. Lett. 93, 023001 (2004)

    Article  CAS  ADS  Google Scholar 

  19. Batelaan, H. Illuminating the Kapitza-Dirac effect with electron matter optics. Rev. Mod. Phys. 79, 929–941 (2007)

    Article  ADS  Google Scholar 

  20. Chu, S. Nobel lecture: The manipulation of neutral particles. Rev. Mod. Phys. 70, 685–706 (1998)

    Article  CAS  ADS  Google Scholar 

  21. Stapelfeldt, H., Sakai, H., Constant, E. & Corkum, P. B. Deflection of neutral molecules using the nonresonant dipole force. Phys. Rev. Lett. 79, 2787–2790 (1997)

    Article  CAS  ADS  Google Scholar 

  22. Fulton, R., Bishop, A. I. & Barker, P. F. Optical Stark decelerator for molecules. Phys. Rev. Lett. 93, 243004 (2004)

    Article  CAS  ADS  Google Scholar 

  23. Henneberger, W. C. Perturbation method for atoms in intense light beams. Phys. Rev. Lett. 21, 838–841 (1968)

    Article  ADS  Google Scholar 

  24. Quesnel, B. & Mora, P. Theory and simulation of the interaction of ultraintense laser pulses with electrons in vacuum. Phys. Rev. E 58, 3719–3732 (1998)

    Article  CAS  ADS  Google Scholar 

  25. Eberly, J. H., Javanainen, J. & Rzazewski, K. Above-threshold ionization. Phys. Rep. 204, 331–383 (1991)

    Article  CAS  ADS  Google Scholar 

Download references


We thank F. Noack for technical support on the laser system and W. Becker, P. B. Corkum, H. R. Reiss and O. Smirnova for discussions.

Author Contributions U.E. and T.N. designed and performed the experiments and analysed the data. All authors contributed to the theoretical understanding and were involved in the completion of the manuscript.

Author information

Authors and Affiliations


Corresponding author

Correspondence to U. Eichmann.

PowerPoint slides

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Eichmann, U., Nubbemeyer, T., Rottke, H. et al. Acceleration of neutral atoms in strong short-pulse laser fields. Nature 461, 1261–1264 (2009).

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI:

This article is cited by


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


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