An efficient source of single photons: a single quantum dot in a micropost microcavity

We have used a single quantum dot in a micropost microcavity to generate triggered single photons. Coupling between the quantum-dot dipole and the confined microcavity mode leads to a large enhancement of the spontaneous emission rate. This, in turn, leads to efficient coupling of the emitted photons into a single traveling-wave mode. Optimization of the microcavity design should lead to nearly unity efficiency, and could also allow for strong coupling and for single-dot lasing.