ABSTRACT
This chapter reviews the characteristic figure of merits of the deterministic single-photon source (SPS) based on a quantum emitter in a semiconductor solid-state system. SPS is a solid-state device capable of emitting single photons on demand. The most fundamental characteristic of the SPS is that it should emit only one photon at a time. This ability is tested in the so-called Hanbury, Brown, and Twiss experiment. A second characteristic for the SPS is that the emitted photons should be quantum mechanically indistinguishable, meaning that the emitted photons should have the same wavelength, phase variation across the pulse, polarization, optical mode profile, etc. The third important characteristic of the SPS is its efficiency or brightness. The ideal SPS should be deterministic and provide single photons on demand. It should act as a "single-photon gun" such that every trigger releases exactly one photon into the collection optics. A major workhorse for generating single photons has been the spontaneous parametric down-conversion process.
