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Spontaneous mirror-symmetry breaking in coupled photonic-crystal nanolasers


Multi-cavity photonic systems, also known as photonic molecules, exhibit multi-well potentials that may prove useful for advanced quantum and nonlinear optics1,2,3,4. A key phenomenon arising in double-well potentials is the spontaneous breaking of inversion symmetry, with a transition to two localized states in the wells, which are mirror images of each other. Although a few theoretical studies have addressed mirror-symmetry breaking in micro- and nanophotonic systems5,6,7, no experimental evidence has been reported to date. Here, we demonstrate spontaneous mirror-symmetry breaking through a pitchfork bifurcation in a photonic molecule composed of two coupled photonic-crystal nanolasers. The coexistence of localized states is shown by switching them with short pulses. This offers exciting prospects for the realization of ultra-compact, integrated, scalable optical flip-flops. Analysis suggests that such symmetry breaking should be possible with a small number of intracavity photons and is thus suitable for quantum correlation devices.

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Figure 1: Photonic molecule
Figure 2: Laser emission of coupled nanocavities
Figure 3: Time-domain measurements and pitchfork bifurcation
Figure 4: Coexistence of broken parity states


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The authors thank A. Amo, J. Bloch, S. Barbay, J. Dudley, N. Treps, J. Tredicce, K. Bencheikh and A. Aspect for comments. This work was supported by the Centre National de la Recherche Scientifique, the Agence Nationale de la Recherche (ANR) (ANR-12-BS04-0011) and the RENATECH network.

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Authors and Affiliations



A.L. and A.M.Y. conceived and designed the experiments. P.H. and S.H. performed the experiments. F.R., G.B. and I.S. fabricated the samples. P.M. provided technical assistance. A.M.Y. performed theoretical analysis and numerical simulations. A.L., P.H. and A.M.Y. co-wrote the paper.

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Correspondence to Alejandro M. Yacomotti.

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The authors declare no competing financial interests.

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Hamel, P., Haddadi, S., Raineri, F. et al. Spontaneous mirror-symmetry breaking in coupled photonic-crystal nanolasers. Nature Photon 9, 311–315 (2015).

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