Single-photon source based on a quantum dot emitting at caesium wavelength

We describe the development and applications of a single-photon source based on a quantum dot embedded in a semiconductor nanowire, which can be precision-tuned to emit similar to 1ns long photons at wavelengths that match the transitions of caesium D-1 line. We discuss interfacing such single-photon source with atomic ensembles and present our experimental results demonstrating a new method of tuning the emission of the quantum dot by condensing inert gas (N-2) on the nanowire. Next, we describe how these single photons at similar to 895nm can be efficiently converted to wavelength suitable for satellite QKD links (similar to 794 nm) and optical fiber links (similar to 1469 nm) using a laser-cooled atomic ensemble that is loaded and confined inside a hollow-core optical fiber. Lastly, we inroduce our proposal of integrating the semiconductor nanowire with a lensed fiber to create a compact single-photon source with improved photon-collection efficiency compared to conventional setups.