Very efficient single-photon sources based on quantum dots in photonic wires

We review the recent development of high-efficiency single photon sources based on a single quantum dot in a photonic wire. Unlike cavity-based devices, very pure single-photon emission and efficiencies exceeding 0.7 photon per pulse are jointly demonstrated under non-resonant pumping conditions. By placing a tip-shaped or trumpet-like tapering at the output end of the wire, a highly directional Gaussian far-field emission pattern is obtained. More generally, a photonic wire containing a quantum dot appears as an attractive template to explore and exploit in a solid-state system the unique optical properties of "one-dimensional atoms".