Dresden 2026 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 55: Quantum Dots and Wires: (Single) Photonics
HL 55.4: Vortrag
Freitag, 13. März 2026, 10:15–10:30, POT/0251
High-quality single photons from cavity-enhanced biexciton-to-exciton transition — •Nils Heinisch1, Francesco Salusti1, Timon L. Baltisberger2, Mark R. Hogg2, Malwina A. Marczak2, Rüdiger Schott3, Sascha R. Valentin3, Andreas D. Wieck3, Arne Ludwig3, Klaus D. Jöns1, Richard J. Warburton2, and Stefan Schumacher1 — 1Department of Physics, CeOPP, and PhoQS, Paderborn University, Germany — 2Department of Physics, University of Basel, Switzerland — 3Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Germany
Generating high-quality photons using the biexciton-exciton cascade benefits from the separability of the photons from the two-photon excitation laser pulse. However, the intrinsic lifetime ratio between biexciton (XX) and exciton (X) states leads to a fundamental limit for the achievable indistinguishability of the single photons [1]. Therefore, the XX must decay much faster than the X. We achieve this with an optical resonator that resonantly enhances the XX-X transition. By optimizing the cavity parameters and avoiding phonon-mediated cavity feeding, we show that high-quality cavity photons originating from XX can be generated. Furthermore, we show that spectral filtering restores single-photon quality in regimes of XX binding energies, where X emission into the cavity is not initially excluded. Our theoretical investigations are joined by key results from the experimental demonstration, which make this approach a major advance in the realization of practical quantum light sources. [1] E. Schöll et al., PRL 125, 233605 (2020). D. Bauch et al., Adv. Quantum Technol. 7, 2300142 (2024).
Keywords: quantum dots; quantum dot cavity systems; single photons; biexciton–exciton cascade