Laser oscillation in a strongly coupled single-quantum-dot–nanocavity system


The strong coupling of photons and matter1 in semiconductor nanocavities has been a test bed for cavity quantum electrodynamics2,3 (QED). Vacuum Rabi oscillation4,5,6,7,8—the coherent exchange of a single quantum between a single quantum dot (SQD) and an optical cavity—and highly efficient cavity-QED lasers9,10,11,12,13,14,15,16,17,18,19 have both been reported. The coexistence of vacuum Rabi oscillation and laser oscillation seems to be contradictory, but it has recently been predicted theoretically that the strong-coupling effect could be sustained in laser oscillation20. Here, we demonstrate the onset of lasing in the strong-coupling regime in an SQD–cavity system. A high-quality semiconductor optical nanocavity and strong SQD–field coupling enabled the onset of lasing while maintaining the fragile coherent exchange of quanta.

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Figure 1: PhC structure and optical characteristics.
Figure 2: Experimental and computed photoluminescence spectra at various pump powers.
Figure 3: Analyses of the experimental and computed photoluminescence spectra.
Figure 4: Mean cavity photon number Nph,g(2)(0) and photoluminescence spectra in lasing and strong-coupling regimes.


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We thank S. Ishida, M. Shirane, S. Ohkouchi, Y. Igarashi, A. Tandaechanurat, K. Watanabe, T. Nakaoka, S. Kako and K. Aoki for their technical support and fruitful discussions. This research was supported by the Special Coordination Funds for Promoting Science and Technology and by KAKENHI 20760030, the Ministry of Education, Culture, Sports, Science and Technology, Japan.

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M.N. processed the samples, carried out the experiments, the simulations and data analyses. N.K. fabricated the semiconductor wafer. S.I. administrated the experiments. Y.O. assisted M.N.’s experiments. Y.A. and M.N. conceived and designed the project. M.N., S.I. and Y.A. wrote the manuscript. All authors contributed to discussion of the results.

Correspondence to M. Nomura or Y. Arakawa.

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Nomura, M., Kumagai, N., Iwamoto, S. et al. Laser oscillation in a strongly coupled single-quantum-dot–nanocavity system. Nature Phys 6, 279–283 (2010).

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