Regensburg 2022 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 36: Materials and Devices for Quantum Technology 2
HL 36.8: Talk
Thursday, September 8, 2022, 17:00–17:15, H36
A solid-state source of single and entangled photons at diamond SiV-center transitions operating at 80 K — •Eddy P. Rugeramigabo1, Xin Cao1, Jingzhong Yang1, Tom Fandrich1, Yiteng Zhang1, Benedikt Brechtken1, Rolf J. Haug1,2, Michael Zopf1, and Fei Ding1,2 — 1Institut für Festkörperphysik, Leibniz Universität Hannover, Germany — 2Laboratorium für Nano- und Quantenengineering, Leibniz Universität Hannover, Germany
Epitaxially grown quantum dots (QDs) hold great potential for the generation of ’flying’ qubits. Coupling these emitters to quantum memories with long coherence times enables the development of hybrid nanophotonic devices incorporating the advantages of both systems. GaAs/AlGaAs QDs based on droplet etching and nanohole infilling exhibit tunable, well-defined optical properties, with emission typically reported at around 780nm. Silicon-vacancy (SiV) centers in diamond show long coherence times and strong interactions with single photons via their zero phonon line (ZPL) at around 737 nm. Here we report the first quantum dot containing material emitting nonclassical light that matches the SiV ZPL. Careful adjustments of the GaAs thickness in the QDs lead to a narrow wavelength distribution (736.2 ± 1.7 nm) and small exciton fine structures (7.0 ± 4.6 eV). Polarization entangled photons are generated via the biexciton-exciton cascade decay with a fidelity of 0.727 ± 0.092. High single photon purity is maintained from 4 K (g(2)(0)= 0.07 ± 0.02) up to 80 K (g(2)(0)= 0.11 ± 0.01), therefore, paving the way towards cost-efficient applications in quantum repeaters and quantum memories.