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:

Complete quantum control of a single quantum dot spin using ultrafast optical pulses

Nature volume 456, pages 218–221 (2008)Cite this article

Abstract

A basic requirement for quantum information processing systems is the ability to completely control the state of a single qubit1,2,3,4,5,6. For qubits based on electron spin, a universal single-qubit gate is realized by a rotation of the spin by any angle about an arbitrary axis. Driven, coherent Rabi oscillations between two spin states can be used to demonstrate control of the rotation angle. Ramsey interference, produced by two coherent spin rotations separated by a variable time delay, demonstrates control over the axis of rotation. Full quantum control of an electron spin in a quantum dot has previously been demonstrated using resonant radio-frequency pulses that require many spin precession periods7,8,9,10. However, optical manipulation of the spin allows quantum control on a picosecond or femtosecond timescale11,12,13,14,15,16,17,18, permitting an arbitrary rotation to be completed within one spin precession period6. Recent work in optical single-spin control has demonstrated the initialization of a spin state in a quantum dot19,20,21,22, as well as the ultrafast manipulation of coherence in a largely unpolarized single-spin state17. Here we demonstrate complete coherent control over an initialized electron spin state in a quantum dot using picosecond optical pulses. First we vary the intensity of a single optical pulse to observe over six Rabi oscillations between the two spin states; then we apply two sequential pulses to observe high-contrast Ramsey interference. Such a two-pulse sequence realizes an arbitrary single-qubit gate completed on a picosecond timescale. Along with the spin initialization and final projective measurement of the spin state, these results demonstrate a complete set of all-optical single-qubit operations.

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

Figure 1: Experimental methods to initialize, control and measure a single electron spin.
Figure 2: Initialization by optical pumping.
Figure 3: Experimental demonstration of Rabi oscillations.
Figure 4: Reconstructed evolution of the Bloch vector.
Figure 5: Experimental demonstration of Ramsey fringes.

Similar content being viewed by others

References

  1. Imamoglu, A. et al. Quantum information processing using quantum dot spins and cavity QED. Phys. Rev. Lett. 83, 4204–4207 (1999)

    Article  ADS  CAS  Google Scholar 

  2. Combescot, M. & Betbeder-Matibet, O. Theory of spin precession monitored by laser pulse. Solid State Commun. 132, 129–134 (2004)

    Article  ADS  CAS  Google Scholar 

  3. Chen, P., Piermarocchi, C., Sham, L. J., Gammon, D. & Steel, D. G. Theory of quantum optical control of a single spin in a quantum dot. Phys. Rev. B 69, 075320 (2004)

    Article  ADS  Google Scholar 

  4. Pryor, C. E. & Flatté, M. E. Predicted ultrafast single-qubit operations in semiconductor quantum dots. Appl. Phys. Lett. 88, 233108 (2006)

    Article  ADS  Google Scholar 

  5. Economou, S. E., Sham, L. J., Wu, Y. & Steel, D. G. Proposal for optical U(1) rotations of electron spin trapped in a quantum dot. Phys. Rev. B 74, 205415 (2006)

    Article  ADS  Google Scholar 

  6. Clark, S. M., Fu, K.-M. C., Ladd, T. D. & Yamamoto, Y. Quantum computers based on electron spins controlled by ultrafast off-resonant single optical pulses. Phys. Rev. Lett. 99, 040501 (2007)

    Article  ADS  Google Scholar 

  7. Koppens, F. H. L. et al. Driven coherent oscillations of a single electron spin in a quantum dot. Nature 442, 766–771 (2006)

    Article  ADS  CAS  Google Scholar 

  8. Tokura, Y., van der Wiel, W., Obata, T. & Tarucha, S. Coherent single electron spin control in a slanting Zeeman field. Phys. Rev. Lett. 96, 047202 (2006)

    Article  ADS  Google Scholar 

  9. Nowack, K. C., Koppens, F. H. L., Nazarov, Y. V. & Vandersypen, L. M. K. Coherent control of a single electron spin with electric fields. Science 318, 1430–1433 (2007)

    Article  ADS  CAS  Google Scholar 

  10. Koppens, F. H. L., Nowack, K. C. & Vandersypen, L. M. K. Spin echo of a single electron spin in a quantum dot. Phys. Rev. Lett. 100, 236802 (2008)

    Article  ADS  CAS  Google Scholar 

  11. Gupta, J. A., Knobel, R., Samarth, N. & Awschalom, D. D. Ultrafast manipulation of electron spin coherence. Science 292, 2458–2461 (2001)

    Article  ADS  CAS  Google Scholar 

  12. Dutt, M. V. G. et al. Ultrafast optical control of electron spin coherence in charged GaAs quantum dots. Phys. Rev. B 74, 125306 (2006)

    Article  ADS  Google Scholar 

  13. Greilich, A. et al. Mode locking of electron spin coherences in singly charged quantum dots. Science 313, 341–345 (2006)

    Article  ADS  CAS  Google Scholar 

  14. Wu, Y. et al. Selective optical control of electron spin coherence in singly charged GaAs-Al0.3Ga0.7As quantum dots. Phys. Rev. Lett. 99, 097402 (2007)

    Article  ADS  Google Scholar 

  15. Greilich, A. et al. Robust manipulation of electron spin coherence in an ensemble of singly charged quantum dots. Phys. Rev. B 75, 233301 (2007)

    Article  ADS  Google Scholar 

  16. Carter, S. G., Chen, Z. & Cundiff, S. T. Ultrafast below-resonance Raman rotation of electron spins in GaAs quantum wells. Phys. Rev. B 76, 201308(R) (2007)

    Article  ADS  Google Scholar 

  17. Berezovsky, J., Mikkelson, M. H., Stoltz, N. G., Coldren, L. A. & Awschalom, D. D. Picosecond coherent optical manipulation of a single electron spin in a quantum dot. Science 320, 349–352 (2008)

    Article  ADS  CAS  Google Scholar 

  18. Fu, K.-M. C. et al. Ultrafast control of donor-bound electron spins with single detuned optical pulses. Nature Phys. 4, 780–784 (2008)

    Article  ADS  CAS  Google Scholar 

  19. Atatüre, M. et al. Quantum-dot spin-state preparation with near-unity fidelity. Science 312, 551–553 (2006)

    Article  ADS  Google Scholar 

  20. Gerardot, B. D. et al. Optical pumping of a single hole spin in a quantum dot. Nature 451, 441–443 (2008)

    Article  ADS  CAS  Google Scholar 

  21. Xu, X. et al. Fast spin state initialization in a singly charged InAs-GaAs quantum dot by optical cooling. Phys. Rev. Lett. 99, 097401 (2007)

    Article  ADS  Google Scholar 

  22. Ramsay, A. J. et al. Fast optical preparation, control, and readout of a single quantum dot spin. Phys. Rev. Lett. 100, 197401 (2008)

    Article  ADS  CAS  Google Scholar 

  23. Petta, J. R. et al. Coherent manipulation of coupled electron spins in semiconductor quantum dots. Science 309, 2180–2184 (2005)

    Article  ADS  CAS  Google Scholar 

  24. Bayer, M. et al. Fine structure of neutral and charged excitons in self-assembled In(Ga)As/(Al)GaAs quantum dots. Phys. Rev. B 65, 195315 (2002)

    Article  ADS  Google Scholar 

  25. Krizhanovskii, D. N. et al. Individual neutral and charged In x Ga1-x As-GaAs quantum dots with strong in-plane optical anisotropy. Phys. Rev. B 72, 161312(R) (2005)

    Article  ADS  Google Scholar 

  26. Cirac, J. I., Zoller, P., Kimble, H. J. & Mabuchi, H. Quantum state transfer and entanglement distribution among distant nodes in a quantum network. Phys. Rev. Lett. 78, 3221–3224 (1997)

    Article  ADS  CAS  Google Scholar 

  27. Berezovsky, J. et al. Nondestructive optical measurements of a single electron spin in a quantum dot. Science 314, 1916–1920 (2006)

    Article  ADS  CAS  Google Scholar 

  28. Atatüre, M., Dreiser, J., Badolato, A. & Imamoglu, A. Observation of Faraday rotation from a single confined spin. Nature Phys. 3, 101–105 (2007)

    Article  ADS  Google Scholar 

  29. Shabaev, A., Efros, A. L., Gammon, D. & Merkulov, I. A. Optical readout and initialization of an electron spin in a single quantum dot. Phys. Rev. B 68, 201305(R) (2003)

    Article  ADS  Google Scholar 

Download references

Acknowledgements

This work was supported by JST/SORST, NICT, MEXT, MURI (ARMY, DAAD 19-03-1-0199) and Special Coordination Funds for Promoting Science and Technology. We thank S. Koseki, S. Götzinger, C. Santori and Q. Zhang for their assistance.

Author information

Authors and Affiliations

  1. E. L. Ginzton Laboratory, Stanford University, Stanford, California 94305, USA ,

    David Press, Thaddeus D. Ladd, Bingyang Zhang & Yoshihisa Yamamoto

  2. National Institute of Informatics, Hitotsubashi 2-1-2, Chiyoda-ku, Tokyo 101-8403, Japan ,

    Thaddeus D. Ladd & Yoshihisa Yamamoto

Authors
  1. David Press
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Thaddeus D. Ladd
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Bingyang Zhang
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Yoshihisa Yamamoto
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to David Press.

Supplementary information

Supplementary Information

This file contains Supplementary Data incorporating Supplementary Figures S1 with Legend. (PDF 223 kb)

PowerPoint slides

Rights and permissions

Reprints and permissions

About this article

Cite this article

Press, D., Ladd, T., Zhang, B. et al. Complete quantum control of a single quantum dot spin using ultrafast optical pulses. Nature 456, 218–221 (2008). https://doi.org/10.1038/nature07530

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature07530

This article is cited by

Comments

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.

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