Over the past decade, exciton-polaritons in semiconductor microcavities have revealed themselves as one of the richest realizations of a light-based quantum fluid1, subject to fascinating new physics and potential applications2,3,4,5,6. For instance, in the regime of large two-body interactions, polaritons can be used to manipulate the quantum properties of a light field7,8,9. In this work, we report on the emergence of quantum correlations in laser light transmitted through a fibre-cavity polariton system. We observe a dispersive shape of the autocorrelation function around the polariton resonance that indicates the onset of this regime. The weak amplitude of these correlations indicates a state that still remains far from a low-photon-number state. Nonetheless, given the underlying physical mechanism7, our work opens up the prospect of eventually using polaritons to turn laser light into single photons.

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We thank S. Martin and D. Taylor from the Commonwealth Scientific and Industrial Research Organisation (Lindfield – New South Wales) for their technical support. This work was funded by the Australian Research Council Centre of Excellence for Engineered Quantum Systems (CE110001013 and CE170100009). A.L., J.B., A.A. and M.R. acknowledge support from the French Agence National de la Recherche (contract no. ANR-16-CE30-0021).

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Author notes

  1. These authors contributed equally: Guillermo Muñoz-Matutano, Andrew Wood, Mattias Johnsson.


  1. Department of Physics and Astronomy, Macquarie University, Sydney, New South Wales, Australia

    • Guillermo Muñoz-Matutano
    • , Andrew Wood
    • , Mattias Johnsson
    • , Xavier Vidal
    • , Ben Q. Baragiola
    • , Andreas Reinhard
    • , Benjamin Besga
    • , Maxime Richard
    •  & Thomas Volz
  2. ARC Centre of Excellence for Engineered Quantum Systems, Macquarie University, Sydney, New South Wales, Australia

    • Guillermo Muñoz-Matutano
    • , Andrew Wood
    • , Mattias Johnsson
    • , Xavier Vidal
    • , Ben Q. Baragiola
    • , Andreas Reinhard
    • , Benjamin Besga
    •  & Thomas Volz
  3. ARC Centre for Quantum Computation and Communication Technology, School of Science, RMIT University, Melbourne, Victoria, Australia

    • Ben Q. Baragiola
  4. Centre de Nanosciences et de Nanotechnologies, CNRS (C2N), Universities Paris-Sud and Paris-Saclay, Palaiseau, France

    • Aristide Lemaître
    •  & Jacqueline Bloch
  5. Univ. Lille, CNRS, UMR 8523, PhLAM - Physique des Lasers Atomes et Molécules, Lille, France

    • Alberto Amo
  6. Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble, France

    • Gilles Nogues
    • , Benjamin Besga
    •  & Maxime Richard


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G.M.-M. and A.W. carried out the spectroscopy and photon correlation experiments and analysed the data. M.J., with the help of B.Q.B., implemented the master equation model and contributed to the analysis of the data. G.M.-M., A.W. and M.J. have equally contributed to this research. X.V. built the spectroscopy set-up. A.R. and B.B. built the cavity microscope and designed the laser machining system for making the fibre cavities. A.L., J.B. and A.A. provided the QW sample and discussed the underlying polariton physics. G.N. carried out the finite-elements simulation of the cavity mode. M.R. and T.V. conceived the central idea of the work and related experiments, supervised the experimental work and contributed to discussions. The manuscript was written by G.M.-M., M.J., M.R. and T.V. with varying contributions from all other authors.

Competing interests

The authors declare no competing interests.

Corresponding authors

Correspondence to Guillermo Muñoz-Matutano or Thomas Volz.

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    Supplementary Sections 1–7, Supplementary Figures 1–11, Supplementary References 1–14

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