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

作者：Madsen K H^*; Ates S; Liu J; Javadi A; Albrecht S M; Yeo I; Stobbe S; Lodahl P

来源：Physical Review B, 2014, 90(15): UNSP 155303.

DOI：10.1103/PhysRevB.90.155303

We demonstrate a single-photon collection efficiency of (44.3 +/- 2.1)% from a quantum dot in a low-Q mode of a photonic-crystal cavity with a single-photon purity of g((2))(0) = (4 +/- 5)% recorded above the saturation power. The high efficiency is directly confirmed by detecting up to 962 +/- 46 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 +/- 0.19 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.

• 出版日期2014-10-6