Letter | Published:

Controlling cavity reflectivity with a single quantum dot

Nature volume 450, pages 857861 (06 December 2007) | Download Citation


Solid-state cavity quantum electrodynamics (QED) systems offer a robust and scalable platform for quantum optics experiments and the development of quantum information processing devices. In particular, systems based on photonic crystal nanocavities and semiconductor quantum dots have seen rapid progress. Recent experiments have allowed the observation of weak1 and strong coupling2,3 regimes of interaction between the photonic crystal cavity and a single quantum dot in photoluminescence. In the weak coupling regime1, the quantum dot radiative lifetime is modified; in the strong coupling regime3, the coupled quantum dot also modifies the cavity spectrum. Several proposals for scalable quantum information networks and quantum computation rely on direct probing of the cavity–quantum dot coupling, by means of resonant light scattering from strongly or weakly coupled quantum dots4,5,6,7,8,9. Such experiments have recently been performed in atomic systems10,11,12 and superconducting circuit QED systems13, but not in solid-state quantum dot–cavity QED systems. Here we present experimental evidence that this interaction can be probed in solid-state systems, and show that, as expected from theory, the quantum dot strongly modifies the cavity transmission and reflection spectra. We show that when the quantum dot is coupled to the cavity, photons that are resonant with its transition are prohibited from entering the cavity. We observe this effect as the quantum dot is tuned through the cavity and the coupling strength between them changes. At high intensity of the probe beam, we observe rapid saturation of the transmission dip. These measurements provide both a method for probing the cavity–quantum dot system and a step towards the realization of quantum devices based on coherent light scattering and large optical nonlinearities from quantum dots in photonic crystal cavities.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1.

    et al. Controlling the spontaneous emission rate of single quantum dots in a two-dimensional photonic crystal. Phys. Rev. Lett. 95, 013904 (2005)

  2. 2.

    et al. Vacuum Rabi splitting with a single quantum dot in a photonic crystal nanocavity. Nature 432, 200–203 (2004)

  3. 3.

    et al. Quantum nature of a strongly coupled single quantum dot-cavity system. Nature 445, 896–899 (2007)

  4. 4.

    , , & Quantum state transfer and entanglement distribution among distant nodes in a quantum network. Phys. Rev. Lett. 78, 3221–3224 (1997)

  5. 5.

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

  6. 6.

    & Scalable photonic quantum computation through cavity-assisted interactions. Phys. Rev. Lett. 92, 127902 (2004)

  7. 7.

    , , & Fault-tolerant quantum repeaters with minimal physical resources and implementations based on single-photon emitters. Phys. Rev. A 72, 052330 (2005)

  8. 8.

    & Dipole induced transparency in drop-filter cavity-waveguide systems. Phys. Rev. Lett. 96, 153601 (2006)

  9. 9.

    , , , & Hybrid quantum repeater based on dispersive CQED interactions between matter qubits and bright coherent light. N. J. Phys. 8, 184 (2006)

  10. 10.

    et al. Photon blockade in an optical cavity with one trapped atom. Nature 436, 87–90 (2005)

  11. 11.

    et al. Coherent operation of a tunable quantum phase gate in cavity QED. Phys. Rev. Lett. 83, 5166–5169 (1999)

  12. 12.

    et al. Seeing a single photon without destroying it. Nature 400, 239–242 (1999)

  13. 13.

    et al. Resolving photon number states in a superconducting circuit. Nature 445, 515–518 (2007)

  14. 14.

    in Cavity Quantum Electrodynamics (ed. Berman, P.) 213–219 (Academic, San Diego, 1994)

  15. 15.

    , , & High-Q photonic nanocavity in a two-dimensional photonic crystal. Nature 425, 944–947 (2003)

  16. 16.

    et al. Local quantum dot tuning on photonic crystal chips. Appl. Phys. Lett. 90, 213110 (2007)

  17. 17.

    et al. Contrast in transmission spectroscopy of a single quantum dot. Appl. Phys. Lett. 90, 221106 (2007)

  18. 18.

    A computational toolbox for quantum and atomic physics. J. Opt. B 1, 424–432 (1999)

  19. 19.

    , , & Real-time cavity QED with single atoms. Phys. Rev. Lett. 80, 4157–4160 (1998)

  20. 20.

    , , & Giant optical nonlinearity induced by a single two-level system interacting with a cavity in the Purcell regime. Phys. Rev. A 75, 053823 (2007)

  21. 21.

    , , , & Generation and transfer of single photons on a photonic crystal chip. Opt. Express 15, 5550–5558 (2007)

  22. 22.

    , , , & Efficient photonic crystal cavity-waveguide couplers. Appl. Phys. Lett. 90, 073102 (2007)

  23. 23.

    , , , & Time evolution and squeezing of the field amplitude in cavity QED. J. Opt. Soc. Am. B 18, 1911–1921 (2001)

  24. 24.

    , & Quantum nondemolition measurement of the photon number via the optical Kerr effect. Phys. Rev. A 32, 2287–2292 (1985)

  25. 25.

    , , , & Generation and manipulation of nonclassical light using photonic crystals. Physica E 32, 466–470 (2006)

Download references


Financial support was provided by the ONR Young Investigator Award, the MURI Center for photonic quantum information systems (ARO/DTO Program), the Okawa Foundation Faculty Research Grant, and the CIS Seed fund. D.E. and I.F. were also supported by the NDSEG fellowship. Work was performed in part at the Stanford Nanofabrication Facility of NNIN supported by the National Science Foundation.

Author information

Author notes

    • Dirk Englund
    • , Andrei Faraon
    •  & Ilya Fushman

    These authors contributed equally to this work.


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

    • Dirk Englund
    • , Andrei Faraon
    • , Ilya Fushman
    •  & Jelena Vučković
  2. Department of Electrical and Computer Engineering, University of California, Santa Barbara, California 93106, USA

    • Nick Stoltz
    •  & Pierre Petroff


  1. Search for Dirk Englund in:

  2. Search for Andrei Faraon in:

  3. Search for Ilya Fushman in:

  4. Search for Nick Stoltz in:

  5. Search for Pierre Petroff in:

  6. Search for Jelena Vučković in:

Corresponding author

Correspondence to Jelena Vučković.

About this article

Publication history






Further reading


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.