Regensburg 2019 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 26: Focus Session: Quantum light sources for applications in quantum communication networks
HL 26.8: Invited Talk
Wednesday, April 3, 2019, 12:30–13:00, H34
Quantum repeater development based on entangled photons from quantum dots — •Michael Zopf1,2, Robert Keil1, Yan Chen1, Jingzhong Yang1,2, Fei Ding1,2, and Oliver G. Schmidt1,3 — 1Institute for Integrative Nanosciences, Leibniz IFW Dresden, Germany — 2Institut für Festkörperphysik, Leibniz Universität Hannover, Germany — 3Material Systems for Nanoelectronics, Technische Universität Chemnitz, Germany
Distributing entangled states over long distances is essential for quantum communication networks. However, due to the transmission losses in optical fibers quantum repeaters have to be developed, as an equivalent for classical signal amplifiers. A promising approach is the combination of the polarization entangled photon emission from semiconductor quantum dots with atomic quantum memories. Here we show that, with an emerging family of GaAs/AlGaAs quantum dots, the stringent requirements for quantum repeaters can be addressed: Large ensembles of polarization-entangled photon emitters are obtained, with precisely tailored emission wavelengths for coupling with rubidium-based quantum memories. Unprecedented entanglement fidelities and photon indistinguishabilities of >90% are observed. Integration with piezoelectric actuators enables wavelength tuning and frequency-stabilization to rubidium transitions. On-demand photon generation with extraction efficiencies up to 65% is achieved with dielectric optical antenna structures, facilitating event-ready applications. These quantum light sources therefore enable entanglement swapping schemes, a major step for quantum repeater applications.