Skip to main content

Thank you for visiting nature.com. 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.

  • Letter
  • Published:

Ultrafast preparation and detection of ring currents in single atoms

Nature Physics volume 14, pages 701–704 (2018)Cite this article

Subjects

Abstract

Quantum particles can penetrate potential barriers by tunnelling1. If that barrier is rotating, the tunnelling process is modified2,3. This is typical for electrons in atoms, molecules or solids exposed to strong circularly polarized laser pulses4,5,6. Here we measure how the transmission probability through a rotating tunnel depends on the sign of the magnetic quantum number m of the electron and thus on the initial direction of rotation of its quantum phase. We further show that our findings agree with a semiclassical picture, in which the electron keeps part of that rotary motion on its way through the tunnel by measuring m-dependent modification of the electron emission pattern. These findings are relevant for attosecond metrology as well as for interpretation of strong-field electron emission from atoms and molecules7,8,9,10,11,12,13,14 and directly demonstrate the creation of ring currents in bound states of ions with attosecond precision. In solids, this could open a way to inducing and controlling ring-current-related topological phenomena15.

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

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

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

Fig. 1: Experimental preparation of ring currents by m-dependent tunnel-ionization.
Fig. 2: Detection of ring currents by momentum-resolved m-dependent tunnel-ionization.
Fig. 3: Energy-resolved electron spectra showing ring current transport during tunnelling.

Similar content being viewed by others

References

  1. Keldysh, L. V. Ionization in the field of a strong electromagnetic wave. Sov. Phys. JETP 20, 1307–1314 (1965).

    MathSciNet  Google Scholar 

  2. Ivanov, M., Spanner, M. & Smirnova, O. Anatomy of strong field ionization. J. Mod. Opt. 52, 165–184 (2005).

    Article  ADS  Google Scholar 

  3. Yudin, G. & Ivanov, M. Nonadiabatic tunnel ionization: Looking inside a laser cycle. Phys. Rev. A 64, 13409 (2001).

    Article  ADS  Google Scholar 

  4. Barth, I. & Smirnova, O. Nonadiabatic tunneling in circularly polarized laser fields: Physical picture and calculations. Phys. Rev. A 84, 63415 (2011).

    Article  ADS  Google Scholar 

  5. Kaushal, J. & Smirnova, O. Nonadiabatic Coulomb effects in strong-field ionization in circularly polarized laser fields. Phys. Rev. A 88, 13421 (2013).

    Article  ADS  Google Scholar 

  6. Zhu, X. et al. Helicity sensitive enhancement of strong-field ionization in circularly polarized laser fields. Opt. Express 24, 4196–4209 (2016).

    Article  ADS  Google Scholar 

  7. Kaushal, J., Morales, F. & Smirnova, O. Opportunities for detecting ring currents using an attoclock setup. Phys. Rev. A 92, 63405 (2015).

    Article  ADS  Google Scholar 

  8. Landsman, A. S. & Keller, U. Attosecond science and the tunnelling time problem. Phys. Rep. 547, 1–24 (2015).

    Article  ADS  MathSciNet  Google Scholar 

  9. Shafir, D. et al. Resolving the time when an electron exits a tunnelling barrier. Nature 485, 343–346 (2012).

    Article  ADS  Google Scholar 

  10. Pedatzur, O. et al. Attosecond tunnelling interferometry. Nat. Phys. 11, 815–819 (2015).

    Article  Google Scholar 

  11. Torlina, L. et al. Interpreting attoclock measurements of tunnelling times. Nat. Phys. 11, 503–508 (2015).

    Article  Google Scholar 

  12. Garg, M. et al. Multi-petahertz electronic metrology. Nature 538, 359–363 (2016).

    Article  ADS  Google Scholar 

  13. Eckle, P. et al. Attosecond ionization and tunneling delay time measurements in helium. Science 322, 1525–1529 (2008).

    Article  ADS  Google Scholar 

  14. Hassan, M. T. et al. Optical attosecond pulses and tracking the nonlinear response of bound electrons. Nature 530, 66–70 (2016).

    Article  ADS  Google Scholar 

  15. Rechtsman, M. et al. Photonic Floquet topological insulators. Nature 496, 196–200 (2013).

    Article  ADS  Google Scholar 

  16. Barth, I. & Manz, J. Electric ring currents in atomic orbitals and magnetic fields induced by short intense circularly polarized π laser pulses. Phys. Rev. A 75, 12510 (2007).

    Article  ADS  Google Scholar 

  17. Fleischer, A. et al. Probing angular correlations in sequential double ionization. Phys. Rev. Lett. 107, 113003 (2011).

    Article  ADS  Google Scholar 

  18. Fechner, L., Camus, N., Ullrich, J., Pfeifer, T. & Moshammer, R. Strong-field tunneling from a coherent superposition of electronic states. Phys. Rev. Lett. 112, 213001 (2014).

    Article  ADS  Google Scholar 

  19. Barth, I. & Smirnova, O. Hole dynamics and spin currents after ionization in strong circularly polarized laser fields. J. Phys. B 47, 204020 (2014).

    Article  ADS  Google Scholar 

  20. Barth, I. & Smirnova, O. Spin-polarized electrons produced by strong-field ionization. Phys. Rev. A 88, 13401 (2013).

    Article  ADS  Google Scholar 

  21. Li, Y. et al. Nonadiabatic tunnel ionization in strong circularly polarized laser fields: counterintuitive angular shifts in the photoelectron momentum distribution. Opt. Express 23, 28801–28807 (2015).

    Article  ADS  Google Scholar 

  22. Hartung, A. et al. Electron spin polarization in strong-field ionization of xenon atoms. Nat. Photon. 10, 526–528 (2016).

    Article  ADS  Google Scholar 

  23. Herath, T., Yan, L., Lee, S. K. & Li, W. Strong-field ionization rate depends on the sign of the magnetic quantum number. Phys. Rev. Lett. 109, 43004 (2012).

    Article  ADS  Google Scholar 

  24. Torlina, L. & Smirnova, O. Time-dependent analytical R-matrix approach for strong-field dynamics. I. One-electron systems. Phys. Rev. A 86, 43408 (2012).

    Article  ADS  Google Scholar 

  25. Torlina, L., Kaushal, J. & Smirnova, O. Time-resolving electron-core dynamics during strong-field ionization in circularly polarized fields. Phys. Rev. A 88, 53403 (2013).

    Article  ADS  Google Scholar 

  26. Torlina, L., Morales, F., Muller, H. G. & Smirnova, O. Ab initio verification of the analytical R-matrix theory for strong field ionization. J. Phys. B 47, 204021 (2014).

    Article  ADS  Google Scholar 

  27. Jagutzki, O. et al. Multiple hit readout of a microchannel plate detector with a three-layer delay-line anode. IEEE Trans. Nucl. Sci. 49, 2477–2483 (2002).

    Article  ADS  Google Scholar 

  28. Ullrich, J. et al. Recoil-ion and electron momentum spectroscopy: reaction-microscopes. Rep. Prog. Phys. 66, 1463–1545 (2003).

    Article  ADS  Google Scholar 

  29. Eckart, S. et al. Nonsequential double ionization by counterrotating circularly polarized two-color laser fields. Phys. Rev. Lett. 117, 133202 (2016).

    Article  ADS  Google Scholar 

  30. Pfeiffer, A. N. et al. Calculation of valence electron motion induced by sequential strong-field ionisation. Mol. Phys. 111, 2283–2291 (2013).

    Article  ADS  Google Scholar 

  31. Nandor, M. J., Walker, M. A., Van Woerkom, L. D. & Muller, H. G. Detailed comparison of above-threshold-ionization spectra from accurate numerical integrations and high-resolution measurements. Phys. Rev. A 60, R1771–R1774 (1999).

    Article  ADS  Google Scholar 

  32. Muller, H. G. An efficient propagation scheme for the time-dependent Schrodinger equation in the velocity gauge. Laser Phys. 9, 138–148 (1999).

    Google Scholar 

  33. Shvetsov-Shilovski, N. I. et al. Semiclassical two-step model for strong-field ionization. Phys. Rev. A 94, 13415 (2016).

    Article  ADS  Google Scholar 

  34. Delone, N. B. & Krainov, V. P. Energy and angular electron spectra for the tunnel ionization of atoms by strong low-frequency radiation. J. Opt. Soc. Am. B 8, 1207–1211 (1991).

    Article  ADS  Google Scholar 

  35. Lemell, C. et al. Low-energy peak structure in strong-field ionization by midinfrared laser pulses: Two-dimensional focusing by the atomic potential. Phys. Rev. A 85, 11403 (2012).

    Article  ADS  Google Scholar 

  36. Eckle, P. et al. Attosecond angular streaking. Nat. Phys. 4, 565–570 (2008).

    Article  Google Scholar 

  37. Pfeiffer, A. N. et al. Attoclock reveals natural coordinates of the laser-induced tunnelling current flow in atoms. Nat. Phys. 8, 76–80 (2012).

    Article  Google Scholar 

  38. Bruner, B. D. et al. Multidimensional high harmonic spectroscopy of polyatomic molecules: detecting sub-cycle laser-driven hole dynamics upon ionization in strong mid-IR laser fields. Faraday Discuss. 194, 369–405 (2016).

    Article  ADS  Google Scholar 

  39. Torlina, L. & Smirnova, O. Coulomb time delays in high harmonic generation. New J. Phys. 19, 23012 (2017).

    Article  Google Scholar 

Download references

Acknowledgements

This work was supported by the DFG Priority Programme ‘Quantum Dynamics in Tailored Intense Fields’ (projects DO 604/29-1, BA 5623/1-1, IV 156/6-1, SM 292/5-1).

Author information

Authors and Affiliations

  1. Institut für Kernphysik, Goethe-Universität Frankfurt am Main, Frankfurt am Main, Germany

    Sebastian Eckart, Maksim Kunitski, Martin Richter, Alexander Hartung, Jonas Rist, Florian Trinter, Kilian Fehre, Nikolai Schlott, Kevin Henrichs, Lothar Ph. H. Schmidt, Till Jahnke, Markus Schöffler & Reinhard Dörner

  2. Max Planck Institute of Microstructure Physics, Halle (Saale), Germany

    Kunlong Liu & Ingo Barth

  3. Max Born Institute, Berlin, Germany

    Jivesh Kaushal, Felipe Morales, Misha Ivanov & Olga Smirnova

  4. Technische Universität Berlin, Berlin, Germany

    Olga Smirnova

Authors
  1. Sebastian Eckart
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Maksim Kunitski
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Martin Richter
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Alexander Hartung
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Jonas Rist
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Florian Trinter
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Kilian Fehre
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Nikolai Schlott
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. Kevin Henrichs
    View author publications

    You can also search for this author in PubMed Google Scholar

  10. Lothar Ph. H. Schmidt
    View author publications

    You can also search for this author in PubMed Google Scholar

  11. Till Jahnke
    View author publications

    You can also search for this author in PubMed Google Scholar

  12. Markus Schöffler
    View author publications

    You can also search for this author in PubMed Google Scholar

  13. Kunlong Liu
    View author publications

    You can also search for this author in PubMed Google Scholar

  14. Ingo Barth
    View author publications

    You can also search for this author in PubMed Google Scholar

  15. Jivesh Kaushal
    View author publications

    You can also search for this author in PubMed Google Scholar

  16. Felipe Morales
    View author publications

    You can also search for this author in PubMed Google Scholar

  17. Misha Ivanov
    View author publications

    You can also search for this author in PubMed Google Scholar

  18. Olga Smirnova
    View author publications

    You can also search for this author in PubMed Google Scholar

  19. Reinhard Dörner
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

S.E., M.K., M.R., A.H., J.R., F.T., K.F., N.S., K.H., L.Ph.H.S., T.J., M.S. and R.D. contributed to the experiment. S.E., M.K., M.R., K.L., I.B., J.K., F.M., M.I., O.S. and R.D. contributed to the theoretical results. S.E., M.K., T.J., M.S. and R.D. performed the analysis of the experimental data. All authors contributed to the manuscript.

Corresponding authors

Correspondence to Sebastian Eckart or Reinhard Dörner.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Figures

Supplementary Figures 1–4

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Eckart, S., Kunitski, M., Richter, M. et al. Ultrafast preparation and detection of ring currents in single atoms. Nature Phys 14, 701–704 (2018). https://doi.org/10.1038/s41567-018-0080-5

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41567-018-0080-5

This article is cited by

Search

Advanced search

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