Berlin 2024 – scientific programme
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QI: Fachverband Quanteninformation
QI 25: Materials and Devices for Quantum Technology II (joint session HL/QI)
QI 25.9: Talk
Thursday, March 21, 2024, 16:30–16:45, EW 203
Optimization of Circular Bragg Grating Resonators for Quantum Dot Photonic Cluster State Sources in the Telecom C-Band — •Yorick Reum, Jochen Kaupp, Simon Betzold, Felix Kohr, Tobias Huber-Loyola, Sven Höfling, and Andreas Pfenning — Technische Physik, Julius-Maximilians-Universität Würzburg, Germany
A major technological bottleneck for the realization of measurement-based optical quantum computing is the production of strings of highly-entangled photons, photonic cluster states. Semiconductor quantum dots (QDs) were shown to be promising candidates for cluster state sources, but spin-decoherence and non-negligible excitionic lifetimes currently limit fidelity and length of the emitted states [1]. This challenge can be tackled by embedding the QD into a cavity with high Purcell enhancement, inducing faster recombination times. We show Purcell-enhanced single-photon emission in the telecom C-band from InAs quantum dots inside circular Bragg grating (“bullseye”) cavities, with excitonic decay times of down to τ = (180 ± 3) ps, corresponding to a Purcell factor of FP = (6.7 ± 0.6) [2]. To further optimize these resonators, we develop best-fitting cavities with 3D finite-difference time-domain simulations and discuss novel strategies for post-fabrication tuning via atomic layer deposition.
[1] Cogan, D., et al., Deterministic generation of indistinguishable photons in a cluster state. Nat. Photon. 17, 324-329 (2023).
[2] Kaupp, J., et al., Purcell-Enhanced Single-Photon Emission in the Telecom C-Band. Adv Quantum Technol. 2023, 2300242.
Keywords: Quantum Dots; Circular Bragg Gratings / Bullseye Resonators; Single Photon Sources; Cluster State Sources; Optical microcavities