A quantum dot single-photon source

We demonstrate a deterministic source for single-photon pulses with nearly 100% efficiency based on pulsed laser excitation of a single-self assembled InAs quantum dot (QD). The single-photon emission at the single exciton ground state transition is ensured by the anharmonicity of the multi-exciton spectrum in combination with slow relaxation of highly excited QD states. We observe single-photon emission both from a free QD and a QD in resonance with a high-quality factor mode of a semiconductor microcavity. In the second scheme, photons are primarily emitted into the cavity mode due to the Purcell effect, which in principle allows for an efficient use of the generated single-photons due to increased output coupling.