Source of indistinguishable single photons based on epitaxial InAs/GaAs quantum dots for integration in quantum computing schemes

The characteristics of single photons emitted by columnar microstructures based on epitaxial microcavity heterostructures with distributed Bragg reflectors, which include self-organized InAs/GaAs quantum dots and have a comparatively low Q factor in the range of 2000–3000, have been studied. It has been shown that a state with a given spin configuration–exciton with a certain polarization or trion–can be initialized in a single quantum dot under the coherent resonant linearly polarized optical pumping by a $\pi$ pulse. The measurement of two-photon interference by the Hong–Ou–Mandel scheme has demonstrated that the degree of indistinguishability of successively emitted single photons is 97 and 93% at a time delay of 2 and 250 ns, respectively. Prospects of application of such sources in optical quantum computing schemes have been discussed.