Stimulated downconversion of single-photon emission in a quantum dot placed in a target-frequency microcavity

We propose efficient frequency-tunable single-photon sources using stimulated frequency downconversion occurring directly in the quantum dot (QD) inside a microcavity. This microcavity should be designed not for the exciton frequency in the QD but for the target frequency that is set by the difference between the exciton resonance and the stimulating laser energies. This frequency downconversion arises from the second-order nonlinear interaction of an exciton (bright or dark) and a light-hole exciton in the stimulating laser field. We present an analytical model for such a process and evaluate its efficiency for a widely sought-after single-photon source for the C-band telecommunications.