Letter | Published:

Strong atom–field coupling for Bose–Einstein condensates in an optical cavity on a chip

Nature volume 450, pages 272276 (08 November 2007) | Download Citation

Abstract

An optical cavity enhances the interaction between atoms and light, and the rate of coherent atom–photon coupling can be made larger than all decoherence rates of the system. For single atoms, this ‘strong coupling regime’ of cavity quantum electrodynamics1,2 has been the subject of many experimental advances. Efforts have been made to control the coupling rate by trapping3,4 the atom and cooling5,6 it towards the motional ground state; the latter has been achieved in one dimension so far5. For systems of many atoms, the three-dimensional ground state of motion is routinely achieved7 in atomic Bose–Einstein condensates (BECs). Although experiments combining BECs and optical cavities have been reported recently8,9, coupling BECs to cavities that are in the strong-coupling regime for single atoms has remained an elusive goal. Here we report such an experiment, made possible by combining a fibre-based cavity10 with atom-chip technology11. This enables single-atom cavity quantum electrodynamics experiments with a simplified set-up and realizes the situation of many atoms in a cavity, each of which is identically and strongly coupled to the cavity mode12. Moreover, the BEC can be positioned deterministically anywhere within the cavity and localized entirely within a single antinode of the standing-wave cavity field; we demonstrate that this gives rise to a controlled, tunable coupling rate. We study the heating rate caused by a cavity transmission measurement as a function of the coupling rate and find no measurable heating for strongly coupled BECs. The spectrum of the coupled atoms–cavity system, which we map out over a wide range of atom numbers and cavity–atom detunings, shows vacuum Rabi splittings exceeding 20 gigahertz, as well as an unpredicted additional splitting, which we attribute to the atomic hyperfine structure. We anticipate that the system will be suitable as a light–matter quantum interface for quantum information13.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

References

  1. 1.

    Strong interactions of single atoms and photons in cavity QED. Phys. Scr. T76, 127–137 (1998)

  2. 2.

    & Exploring the Quantum: Atoms, Cavities and Photons (Oxford Univ. Press, Oxford, UK, 2006)

  3. 3.

    , & Trapping of single atoms in cavity QED. Phys. Rev. Lett. 83, 4987–4990 (1999)

  4. 4.

    , , & Trapping an atom with single photons. Nature 404, 365–368 (2000)

  5. 5.

    , , , & Cooling to the ground state of axial motion for one atom strongly coupled to an optical cavity. Phys. Rev. Lett. 97, 083602 (2006)

  6. 6.

    et al. Cavity cooling of a single atom. Nature 428, 50–52 (2004)

  7. 7.

    & Bose–Einstein condensation of atomic gases. Nature 416, 211–218 (2002)

  8. 8.

    , , & Correlations and counting statistics of an atom laser. Phys. Rev. Lett. 95, 090404 (2005)

  9. 9.

    , , , & Superradiant Rayleigh scattering and collective atomic recoil lasing in a ring cavity. Phys. Rev. Lett. 98, 053603 (2007)

  10. 10.

    et al. A stable fiber-based Fabry–Perot cavity. Appl. Phys. Lett. 89, 111110 (2006)

  11. 11.

    & Magnetic microtraps for ultracold atoms. Rev. Mod. Phys. 79, 235–289 (2007)

  12. 12.

    et al. Cavity QED with a Bose–Einstein condensate. Nature doi: 10.1038/nature06120 (this issue).

  13. 13.

    , , & Long-distance quantum communication with atomic ensembles and linear optics. Nature 414, 413–418 (2001)

  14. 14.

    Coherence in spontaneous radiation processes. Phys. Rev. 93, 99–110 (1954)

  15. 15.

    , & Deterministic atom–light quantum interface. Adv. At. Mol. Opt. Phys. 54, 81–130 (2006)

  16. 16.

    , , & Interfacing collective atomic excitations and single photons. Phys. Rev. Lett. 98, 183601 (2007)

  17. 17.

    & Approximate solutions for an N-molecule–radiation-field Hamiltonian. Phys. Rev. 188, 692–695 (1969)

  18. 18.

    & Does matter wave amplification work for fermions? Phys. Rev. Lett. 86, 4203–4206 (2001)

  19. 19.

    et al. Superradiant Rayleigh scattering from a Bose–Einstein condensate. Science 285, 571–574 (1999)

  20. 20.

    , & Refractive index of a dilute Bose gas. Phys. Rev. A 51, 3896–3901 (1995)

  21. 21.

    , & Probing quantum phases of ultracold atoms in optical lattices by transmission spectra in cavity quantum electrodynamics. Nature Phys. 3, 319–323 (2007)

  22. 22.

    et al. Quantum information processing in optical lattices and magnetic microtraps. Fortschr. Phys. 54, 702–718 (2006)

  23. 23.

    et al. Observation of strong coupling between one atom and a monolithic microresonator. Nature 443, 671–674 (2006)

  24. 24.

    Quasi-1D Bose–Einstein condensates in the dimensional crossover regime. Europhys. Lett. 66, 771–777 (2004)

  25. 25.

    , & Observation of normal-mode splitting for an atom in an optical cavity. Phys. Rev. Lett. 68, 1132–1135 (1992)

  26. 26.

    , , , & Collective light forces on atoms in a high-finesse cavity. N. J. Phys. 3, 11 (2001)

  27. 27.

    , , & Measurement of intracavity quantum fluctuations of light using an atomic fluctuation bolometer. Preprint at 〈〉 (2007)

  28. 28.

    , & Nondestructive dynamic detectors for Bose–Einstein condensates. Phys. Rev. A 67, 043609 (2003)

  29. 29.

    , , & Collapse and revival of the matter wave field of a Bose–Einstein condensate. Nature 419, 51–54 (2002)

  30. 30.

    et al. Extracting atoms on demand with lasers. Phys. Rev. A 71, 053601 (2005)

  31. 31.

    et al. Atom-chip Bose–Einstein condensation in a portable vacuum cell. Phys. Rev. A 70, 053606 (2004)

  32. 32.

    , , & Bose–Einstein condensation on a microelectronic chip. Nature 413, 498–501 (2001)

  33. 33.

    , & Atomic micromanipulation with magnetic surface traps. Phys. Rev. Lett. 83, 3398–3401 (1999)

  34. 34.

    , , & Thermally induced losses in ultra-cold atoms magnetically trapped near room-temperature surfaces. J. Low Temp. Phys. 133, 229–238 (2003)

  35. 35.

    Microchip traps and Bose–Einstein condensation. Appl. Phys. B 74, 469–487 (2002)

Download references

Acknowledgements

We thank J. Hare and F. Orucevic for support in producing the fibre mirror surfaces, and F. Gerbier for the calculation of condensate size in the crossover regime. We acknowledge discussions with Y. Castin and J. Dalibard about atom–light interaction in BECs, as well as with T. W. Hänsch, I. Cirac, P. Treutlein and R. Long. This work was supported by a European Young Investigator Award (EURYI), a Chaire d’Excellence of the French Ministry for Research, and by the EU (‘Atom Chips’ Research Training Network and ‘SCALA’ Integrated Programme). The Atom Chip team at Laboratoire Kastler Brossel is part of the Institut Francilien de Recherche sur les Atomes Froids (IFRAF).

Author information

Author notes

    • Yves Colombe
    •  & Tilo Steinmetz

    These authors contributed equally to this work.

    • Felix Linke

    Present address: BMW Group, Abt. Instrumentierung und Displays, Knorrstr. 147, D-80788 München, Germany.

Affiliations

  1. Laboratoire Kastler Brossel, ENS/UPMC-Paris 6/CNRS, 24 rue Lhomond, 75005 Paris, France

    • Yves Colombe
    • , Tilo Steinmetz
    • , Guilhem Dubois
    • , Felix Linke
    •  & Jakob Reichel
  2. Max-Planck-Institut für Quantenoptik/LMU, Schellingstr. 4, 80799 München, Germany

    • Tilo Steinmetz
    •  & David Hunger

Authors

  1. Search for Yves Colombe in:

  2. Search for Tilo Steinmetz in:

  3. Search for Guilhem Dubois in:

  4. Search for Felix Linke in:

  5. Search for David Hunger in:

  6. Search for Jakob Reichel in:

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Jakob Reichel.

Supplementary information

PDF files

  1. 1.

    Supplementary Notes

    This file contains Supplementary Notes with additional information on collective atom-field interaction and describes two models that we refer to in the letter: the multilevel coupling model that predicts an anticrossing in the vacuum-Rabi spectrum, and the momentum-diffusion model for cavity field-induced heating of the atom cloud.

About this article

Publication history

Received

Accepted

Published

DOI

https://doi.org/10.1038/nature06331

Further reading

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.