Regensburg 2025 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 42: Quantum Dots and Wires: Optics I

HL 42.2: Talk

Wednesday, March 19, 2025, 17:15–17:30, H17

Development and deterministic fabrication of electrically controlled quantum dot molecule bullseye resonators — •Setthanat Wijitpatima¹, Normen Auler², Binamra Shrestha², Sven Rodt¹, Arne Ludwig³, Dirk Reuter², and Stephan Reitzenstein¹ — ¹Institute of Solid-State Physics, Technische Universität Berlin, D-10623 Berlin, Germany — ²Department of Physics, Universität Paderborn, Warburger Str. 100, 33098 Paderborn, Germany — ³Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Universitätsstraße 150, 44780 Bochum, Germany

Quantum information can be encoded in the polarization states of photons as flying qubits and decoded in the spin states of solid-state systems as stationary qubits, providing robust platforms for quantum information processing. Quantum dot molecules (QDMs) are particularly promising for this purpose, as their singlet-triplet qubits are immune to spin dephasing, enabling temporally stable spin-photon interfaces. Toward real-world applications, QDM devices with high photon extraction efficiency (PEE) are required, motivating the integration of QDMs into nanophotonic structures, such as circular Bragg gratings (CBGs) which yield broadband enhancement of PEE and moderate Purcell enhancement. However, applying the CBG concept to QDMs has been challenging since precise electrical control is crucially needed to operate QDMs properly. In this work, we demonstrate the fabrication of QDM-CBG devices, providing a crucial step toward scalable and efficient quantum technologies.

Keywords: InGaAs Quantum Dots; Quantum Dot Molecules; Circular Bragg Grating; Electron Beam Lithography; Cathodoluminescence