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arXiv · 1402.6967

Efficient out-coupling of high-purity single photons from a coherent quantum dot in a photonic-crystal cavity

K. H. Madsen·S. Ates·J. Liu·A. Javadi·S. M. Albrecht·I. Yeo·S. Stobbe·P. Lodahl
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Abstract

We demonstrate a single-photon collection efficiency of $(44.3\pm2.1)\%$ from a quantum dot in a low-Q mode of a photonic-crystal cavity with a single-photon purity of $g^{(2)}(0)=(4\pm5)\%$ recorded above the saturation power. The high efficiency is directly confirmed by detecting up to $962\pm46$ kilocounts per second on a single-photon detector on another quantum dot coupled to the cavity mode. The high collection efficiency is found to be broadband, as is explained by detailed numerical simulations. Cavity-enhanced efficient excitation of quantum dots is obtained through phonon-mediated excitation and under these conditions, single-photon indistinguishability measurements reveal long coherence times reaching $0.77\pm0.19$ ns in a weak-excitation regime. Our work demonstrates that photonic crystals provide a very promising platform for highly integrated generation of coherent single photons including the efficient out-coupling of the photons from the photonic chip.

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K. H. Madsen, S. Ates, J. Liu, A. Javadi, S. M. Albrecht, I. Yeo, S. Stobbe, P. Lodahl. 2014-10-02. Efficient out-coupling of high-purity single photons from a coherent quantum dot in a photonic-crystal cavity. https://doi.org/10.1103/physrevb.90.155303

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