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Towards polariton blockade of confined exciton–polaritons


Cavity–polaritons in semiconductor microstructures have emerged as a promising system for exploring non-equilibrium dynamics of many-body systems1. Key advances in this field, including the observation of polariton condensation2, superfluidity3, realization of topological photonic bands4, and dissipative phase transitions5,6,7, generically allow for a description based on a mean-field Gross–Pitaevskii formalism. Observation of polariton intensity squeezing8,9 and decoherence of a polarization entangled photon pair by a polariton condensate10, on the other hand, demonstrate quantum effects that show up at high polariton occupancy. Going beyond and into the regime of strongly correlated polaritons requires the observation of a photon blockade effect11,12 where interactions are strong enough to suppress double occupancy of a photonic lattice site. Here, we report evidence of quantum correlations between polaritons spatially confined in a fibre cavity. Photon correlation measurements show that careful tuning of the coupled system can lead to a modest reduction of simultaneous two-polariton generation probability by 5%. Concurrently, our experiments allow us to measure the polariton interaction strength, thereby resolving the controversy stemming from recent experimental reports13. Our findings constitute an essential step towards the realization of strongly interacting photonic systems.

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Fig. 1: Experimental set-up for cavity–polaritons.
Fig. 2: Optimization of polariton parameters.
Fig. 3: Quantum correlations between polaritons.

Data availability

The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.


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This work was supported by the Swiss National Science Foundation (SNSF) through a DACH project 200021E-158569-1, SNSF National Centre of Competence in Research – Quantum Science and Technology (NCCR QSIT) and an ERC Advanced investigator grant (POLTDES). The Würzburg Group acknowledges support by the state of Bavaria, and the DFG within project SCHN1376-3.1.

Author information




A.D., T.F. and A.I. supervised the project. T.F. designed the experiment. A.D. and T.F. carried out the measurements. A.S., C.S., and S.H. grew the sample. A.D. and A.I. wrote the manuscript.

Corresponding author

Correspondence to Ataç İmamoğlu.

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The authors declare no competing interests.

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Supplementary information

Supplementary Information

Supplementary Sections 1–4, Supplementary Figures 1–4, Supplementary References 1–5

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Delteil, A., Fink, T., Schade, A. et al. Towards polariton blockade of confined exciton–polaritons. Nature Mater 18, 219–222 (2019).

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