Solid-state triggered single photon sources

Abstract

The correlation between the photons emitted by an optically pumped single quantum dot is investigated. The correlation function on a single dot isolated in a mesa shows that only one photon is emitted at a time at the exciton frequency. Moreover, cross-correlation experiments provide evidence of the sequential de-excitation of the quantum dot, yielding a radiative cascade that produces two single photons with a definite order. These quantum states of light can be generated with a high quantum efficiency, with the use of cavity effects: surrounding the dot by a pillar microcavity not only increases significantly the single photon flux but also allows the preparation of single photon all in the same quantum state (same spatial mode and same polarization).