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Emergence of quantum correlations from interacting fibre-cavity polaritons


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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Fig. 1: Polariton excitation ladder and experimental set-up.
Fig. 2: Anticrossing of the polariton states and lifetimes.
Fig. 3: Quantum-correlated photons with cavity-exciton detuning.
Fig. 4: Polariton–polariton interaction constant.

Data availability

All data presented in this work are available on request from the authors.


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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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Authors and Affiliations



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.

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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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Muñoz-Matutano, G., Wood, A., Johnsson, M. et al. Emergence of quantum correlations from interacting fibre-cavity polaritons. Nature Mater 18, 213–218 (2019).

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