title: Wavelength-tunable sources of entangled photons interfaced with atomic vapours.
abstract: The prospect of using the quantum nature of light for secure communication keeps spurring the search and investigation of suitable sources of entangled photons. A single semiconductor quantum dot is one of the most attractive, as it can generate indistinguishable entangled photons deterministically and is compatible with current photonic-integration technologies. However, the lack of control over the energy of the entangled photons is hampering the exploitation of dissimilar quantum dots in protocols requiring the teleportation of quantum entanglement over remote locations. Here we introduce quantum dot-based sources of polarization-entangled photons whose energy can be tuned via three-directional strain engineering without degrading the degree of entanglement of the photon pairs. As a test-bench for quantum communication, we interface quantum dots with clouds of atomic vapours, and we demonstrate slow-entangled photons from a single quantum emitter. These results pave the way towards the implementation of hybrid quantum networks where entanglement is distributed among distant parties using optoelectronic devices.
authors.affiliation: Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenbergerstr. 69, A-4040 Linz, Austria.
authors.forename: Rinaldo
authors.initials: R
authors.lastname: Trotta
authors.affiliation: Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenbergerstr. 69, A-4040 Linz, Austria.
authors.forename: Javier
authors.initials: J
authors.lastname: Martín-Sánchez
authors.affiliation: Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenbergerstr. 69, A-4040 Linz, Austria.
authors.forename: Johannes S
authors.initials: JS
authors.lastname: Wildmann
authors.affiliation: Forschungszentrum Mikrotechnik, FH Vorarlberg, Hochschulstr. 1, A-6850 Dornbirn, Austria.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Piredda
authors.affiliation: Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenbergerstr. 69, A-4040 Linz, Austria.
authors.forename: Marcus
authors.initials: M
authors.lastname: Reindl
authors.affiliation: Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenbergerstr. 69, A-4040 Linz, Austria.
authors.forename: Christian
authors.initials: C
authors.lastname: Schimpf
authors.affiliation: Institute for Integrative Nanosciences, IFW Dresden, Helmholtzstr. 20, D-01069 Dresden, Germany.|Paul-Drude-Institut für Festkörperelektronik, Hausvogteilplatz 5-7, 10117 Berlin, Germany.
authors.forename: Eugenio
authors.initials: E
authors.lastname: Zallo
authors.affiliation: Forschungszentrum Mikrotechnik, FH Vorarlberg, Hochschulstr. 1, A-6850 Dornbirn, Austria.
authors.forename: Sandra
authors.initials: S
authors.lastname: Stroj
authors.affiliation: Forschungszentrum Mikrotechnik, FH Vorarlberg, Hochschulstr. 1, A-6850 Dornbirn, Austria.
authors.forename: Johannes
authors.initials: J
authors.lastname: Edlinger
authors.affiliation: Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenbergerstr. 69, A-4040 Linz, Austria.
authors.forename: Armando
authors.initials: A
authors.lastname: Rastelli
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