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HL: Fachverband Halbleiterphysik
HL 30: Poster 2
HL 30.9: Poster
Donnerstag, 8. September 2022, 11:00–13:00, P3
Strain-tunable GaAs quantum dot-based circular Bragg gratings towards entangled photon pairs with high indistinguishability — •Chenxi Ma1, Jingzhong Yang1, Constantin Schmidt1, Xin Cao1, Yiteng Zhang1, Maximilian Heller1, Jürgen Becker2, Eddy P. Rugeramigabo1, Michael Zopf1, and Fei Ding1,3 — 1Institut für Festkörperphysik, Leibniz Universität Hannover, Hannover, Germany — 2Institut für Mikroproduktionstechnik, Leibniz Universität Hannover, Garbsen, Germany — 3Laboratorium für Nano- und Quantenengineering, Leibniz Universität Hannover, Hannover, Germany
The on-demand generation of bright entangled photon pairs is an attractive goal for the realization of quantum communication networks. Epitaxial GaAs quantum dots (QDs), grown via local droplet etching and nanohole infilling, are promising candidates because they are symmetric and strain-free. This leads to small exciton fine structures and high entanglement fidelities of photons emitted from the biexciton-exciton cascade. However, the photon indistinguishability is intrinsically limited in this scheme. GaAs QDs also suffer from inefficient photon extraction, which was addressed by embedding QDs in circular Bragg gratings. Here, we propose to engineer the cavity mode to match the biexciton transition with the assistance of strain-tuning techniques. The resulting asymmetric Purcell enhancement will increase the decay rate of the biexciton transition and consequently improve the photon indistinguishability. This heterogeneous photonic nanostructure can serve as a blueprint for future quantum communication devices.