Single-photon sources

摘要: The concept of the photon, central to Einstein's explanation photoelectric effect, is exactly 100 years old. Yet, while photons have been detected individually for more than 50 years, devices producing individual on demand only appeared in last few years. New concepts single-photon sources, or 'photon guns', originated from recent progress optical detection, characterization and manipulation single quantum objects. Single emitters usually deliver one at a time. This so-called antibunching emitted can arise various mechanisms, but ensures that probability obtaining two same time remains negligible. We briefly recall basic optics discuss potential applications states processing information: cryptography, computing communication. A photon gun's properties are significantly improved by coupling it resonant cavity mode, either Purcell strong-coupling regimes. early production with atomic beams, operation principles macroscopic parametric which used an overwhelming majority quantum-optical experiments. then review photophysical spectroscopic compare advantages weaknesses nanometre-scale objects as sources: atoms ions gas phase and, condensed matter, organic molecules, defect centres, semiconductor nanocrystals heterostructures. As new generations sources developed, cavities nano-fabrication techniques lead characteristics, delivery rates spectral ranges. Judging brisk pace progress, we expect soon proceed demonstrations bring them first practical uses information.