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.

  • Article
  • Published:

Integrated multi-wavelength control of an ion qubit

Nature volume 586, pages 538–542 (2020)Cite this article

Subjects

A Publisher Correction to this article was published on 19 January 2021

This article has been updated

Abstract

Monolithic integration of control technologies for atomic systems is a promising route to the development of quantum computers and portable quantum sensors1,2,3,4. Trapped atomic ions form the basis of high-fidelity quantum information processors5,6 and high-accuracy optical clocks7. However, current implementations rely on free-space optics for ion control, which limits their portability and scalability. Here we demonstrate a surface-electrode ion-trap chip8,9 using integrated waveguides and grating couplers, which delivers all the wavelengths of light required for ionization, cooling, coherent operations and quantum state preparation and detection of Sr+ qubits. Laser light from violet to infrared is coupled onto the chip via an optical-fibre array, creating an inherently stable optical path, which we use to demonstrate qubit coherence that is resilient to platform vibrations. This demonstration of CMOS-compatible integrated photonic surface-trap fabrication, robust packaging and enhanced qubit coherence is a key advance in the development of portable trapped-ion quantum sensors and clocks, providing a way towards the complete, individual control of larger numbers of ions in quantum information processing systems.

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: Ion-trap-integrated photonic elements and experimental setup.
Fig. 2: Integrated photonic beam profiles measured via microscope and subsequently verified via ion interactions in situ.
Fig. 3: Ion state detection and spectroscopy with integrated light delivery.
Fig. 4: Vibration insensitivity when delivering qubit-control light via monolithically integrated optics and direct fibre-to-chip coupling.

Similar content being viewed by others

Data availability

All relevant data are available from the corresponding authors on request.

Change history

  • 19 January 2021

    A Correction to this paper has been published: https://doi.org/10.1038/s41586-020-03104-8

References

  1. Mehta, K. K. et al. Integrated optical addressing of an ion qubit. Nat. Nanotechnol. 11, 1066–1070 (2016).

    Article  ADS  CAS  Google Scholar 

  2. Slichter, D. H. et al. UV-sensitive superconducting nanowire single photon detectors for integration in an ion trap. Opt. Express 25, 8705–8720 (2017).

    Article  ADS  CAS  Google Scholar 

  3. Todaro, S. L. et al. State readout of a trapped ion qubit using a trap-integrated superconducting photon detector. Preprint at https://arxiv.org/abs/2008.00065 (2020).

  4. Stuart, J. et al. Chip-integrated voltage sources for control of trapped ions. Phys. Rev. Appl. 11, 024010 (2019).

    Article  ADS  CAS  Google Scholar 

  5. Cirac, J. I. & Zoller, P. Quantum computations with cold trapped ions. Phys. Rev. Lett. 74, 4091–4094 (1995).

    Article  ADS  CAS  Google Scholar 

  6. Bruzewicz, C. D., Chiaverini, J., McConnell, R. & Sage, J. M. Trapped-ion quantum computing: Progress and challenges. Appl. Phys. Rev. 6, 021314 (2019).

    Article  ADS  Google Scholar 

  7. Brewer, S. M. et al. 27Al+ quantum-logic clock with a systematic uncertainty below 10−18. Phys. Rev. Lett. 123, 033201 (2019).

    Article  ADS  CAS  Google Scholar 

  8. Chiaverini, J. et al. Surface-electrode architecture for ion-trap quantum information processing. Quantum Inf. Comput. 5, 419–439 (2005).

    MathSciNet  CAS  MATH  Google Scholar 

  9. Seidelin, S. et al. Microfabricated surface-electrode ion trap for scalable quantum information processing. Phys. Rev. Lett. 96, 253003 (2006).

    Article  ADS  CAS  Google Scholar 

  10. Leibfried, D., Blatt, R., Monroe, C. & Wineland, D. Quantum dynamics of single trapped ions. Rev. Mod. Phys. 75, 281–324 (2003).

    Article  ADS  CAS  Google Scholar 

  11. Monroe, C. & Kim, J. Scaling the ion trap quantum processor. Science 339, 1164–1169 (2013).

    Article  ADS  CAS  Google Scholar 

  12. Gaebler, J. P. et al. High-fidelity universal gate set for 9Be+ ion qubits. Phys. Rev. Lett. 117, 060505 (2016).

    Article  ADS  CAS  Google Scholar 

  13. Ballance, C. J., Harty, T. P., Linke, N. M., Sepiol, M. A. & Lucas, D. M. High-fidelity quantum logic gates using trapped-ion hyperfine qubits. Phys. Rev. Lett. 117, 060504 (2016).

    Article  ADS  CAS  Google Scholar 

  14. Nam, Y. et al. Ground-state energy estimation of the water molecule on a trapped-ion quantum computer. npj Quantum Inf. 6, 33 (2020).

    Article  ADS  Google Scholar 

  15. Wright, K. et al. Benchmarking an 11-qubit quantum computer. Nat. Commun. 10, 5465 (2019).

    Article  ADS  Google Scholar 

  16. Ruster, T. et al. Entanglement-based DC magnetometry with separated ions. Phys. Rev. X 7, 031050 (2017).

    Google Scholar 

  17. Delehaye, M. & Lacrote, C. Single-ion, transportable optical atomic clocks. J. Mod. Opt. 65, 622–639 (2018).

    Article  ADS  MathSciNet  CAS  Google Scholar 

  18. Thom, J., Yuen, B., Wilpers, G., Riis, E. & Sinclair, A. G. Intensity stabilisation of optical pulse sequences for coherent control of laser-driven qubits. Appl. Phys. B 124, 90 (2018).

    Article  ADS  Google Scholar 

  19. Dalgoutte, D. G. & Wilkinson, C. D. W. Thin grating couplers for integrated optics: an experimental and theoretical study. Appl. Opt. 14, 2983–2998 (1975).

    Article  ADS  CAS  Google Scholar 

  20. Sorace-Agaskar, C. et al. Versatile silicon nitride and alumina integrated photonic platforms for the ultraviolet to short-wave infrared. IEEE J. Sel. Top. Quantum Electron. 25, 1–15 (2019).

    Article  Google Scholar 

  21. Almeida, V. R., Panepucci, R. R. & Lipson, M. Nanotaper for compact mode conversion. Opt. Lett. 28, 1302–1304 (2003).

    Article  ADS  CAS  Google Scholar 

  22. Sage, J. M., Kerman, A. J. & Chiaverini, J. Loading of a surface-electrode ion trap from a remote, precooled source. Phys. Rev. A 86, 013417 (2012).

    Article  ADS  Google Scholar 

  23. Wang, S. X. et al. Laser-induced charging of microfabricated ion traps. J. Appl. Phys. 110, 104901 (2011).

    Article  ADS  Google Scholar 

  24. Bruzewicz, C. D., McConnell, R., Chiaverini, J. & Sage, J. M. Scalable loading of a two-dimensional trapped-ion array. Nat. Commun. 7, 13005 (2016).

    Article  ADS  CAS  Google Scholar 

  25. Mehta, K. K. & Ram, R. J. Precise and diffraction-limited waveguide-to-free-space focusing gratings. Sci. Rep. 7, 2019 (2017).

    Article  ADS  Google Scholar 

  26. Safronova, U., Safronova, M. & Johnson, W. Forbidden M1 and E2 transitions in monovalent atoms and ions. Phys. Rev. A 95, 042507 (2017).

    Article  ADS  Google Scholar 

  27. Mehta, K. K. et al. Integrated optical multi-ion quantum logic. Nature https://www.nature.com/articles/s41586-020-2823-6 (2020).

  28. Mehta, K. K. et al. Ion traps fabricated in a CMOS foundry. Appl. Phys. Lett. 105, 044103 (2014).

    Article  ADS  Google Scholar 

  29. Bruzewicz, C. D., Sage, J. M. & Chiaverini, J. Measurement of ion motional heating rates over a range of trap frequencies and temperatures. Phys. Rev. A 91, 041402 (2015).

    Article  ADS  Google Scholar 

  30. Bauters, J. F. et al. Ultra-low-loss high-aspect-ratio Si3N4 waveguides. Opt. Express 19, 3163–3174 (2011).

    Article  ADS  CAS  Google Scholar 

  31. Roos, C. Controlling the Quantum State of Trapped Ions. PhD thesis, Univ. Innsbruck (2000).

  32. West, G. N. et al. Low-loss integrated photonics for the blue and ultraviolet regime. APL Photon. 4, 026101 (2019).

    Article  ADS  Google Scholar 

Download references

Acknowledgements

We thank P. Murphy, C. Thoummaraj and K. Magoon for assistance with chip packaging, and P. Hassett and K. Yu for chip-facet polishing. This material is based on work supported by the Department of Defense under Air Force Contract number FA8702-15-D-0001. Any opinions, findings, conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the Department of Defense.

Author information

Authors and Affiliations

  1. Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA, USA

    R. J. Niffenegger, J. Stuart, C. Sorace-Agaskar, D. Kharas, S. Bramhavar, C. D. Bruzewicz, W. Loh, R. T. Maxson, R. McConnell, D. Reens, J. M. Sage & J. Chiaverini

  2. Massachusetts Institute of Technology, Cambridge, MA, USA

    J. Stuart, G. N. West, J. M. Sage & J. Chiaverini

Authors
  1. R. J. Niffenegger
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. J. Stuart
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. C. Sorace-Agaskar
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. D. Kharas
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. S. Bramhavar
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. C. D. Bruzewicz
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. W. Loh
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. R. T. Maxson
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. R. McConnell
    View author publications

    You can also search for this author in PubMed Google Scholar

  10. D. Reens
    View author publications

    You can also search for this author in PubMed Google Scholar

  11. G. N. West
    View author publications

    You can also search for this author in PubMed Google Scholar

  12. J. M. Sage
    View author publications

    You can also search for this author in PubMed Google Scholar

  13. J. Chiaverini
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

J.M.S. and J.C. conceived the work. C.S.-A. and S.B. designed the integrated optical components; D.K. oversaw the fabrication of the devices. R.J.N. performed the experiments, with assistance from J.S., C.D.B., D.R., R.M., R.T.M., G.N.W. and W.L.; R.J.N. analysed the data. All authors discussed the results and contributed to writing the paper.

Corresponding authors

Correspondence to R. J. Niffenegger, J. M. Sage or J. Chiaverini.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Peer review information Nature thanks Jungsang Kim and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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

Extended data figures and tables

Extended Data Fig. 1 Plan view of one of the grating couplers superimposed on the trap electrode metal (partial).

The single-mode (SM) waveguide is tapered to provide a wider beam at the grating coupler. The grating teeth are formed via a partial etch into the waveguide material beneath a window in the electrode metal. The gratings used are forward-emitting, designed to emit a beam to the ion location as depicted, but 55 μm above the surface of the metal.

Extended Data Fig. 2 Integrated photonic beam profiles measured from camera-recorded images.

a, High-numerical-aperture microscope images of the beams are taken while vertically scanning the focal plane above the chip. b, c, Laser light is emitted from the grating couplers and imaged at a height of z = 0 (b) and z = 25 μm (c) above the ion-trap electrodes.

Extended Data Fig. 3 Ion interaction profile of 408-nm light, which was used as a proxy for 405-nm light.

Error bars indicate the standard error of the mean.

Extended Data Table 1 Summary of coupling and on-chip optical losses versus wavelength
Full size table

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Niffenegger, R.J., Stuart, J., Sorace-Agaskar, C. et al. Integrated multi-wavelength control of an ion qubit. Nature 586, 538–542 (2020). https://doi.org/10.1038/s41586-020-2811-x

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41586-020-2811-x

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