Converting single photons from an InAs/GaAs quantum dot into the ultraviolet: preservation of second-order correlations

Wavelength conversion at the single-photon level is required to forge a quantum network from distinct quantum devices. Such devices include solid-state emitters of single or entangled photons, as well as network nodes based on atoms or ions. Here we demonstrate the conversion of single photons emitted from a III-V semiconductor quantum dot at 853nm via sum frequency conversion to the wavelength of the strong transition of Yb+ ions at 370 nm. We measure the secondorder correlation function of both the unconverted and the converted photon and show that the single-photon character of the quantum dot emission is preserved during the conversion process. (C) 2022 Optica Publishing Group