Regensburg 2025 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 36: Materials and Devices for Quantum Technology II

HL 36.11: Talk

Wednesday, March 19, 2025, 17:45–18:00, H13

Charge-tunable quantum dot single photon sources for quantum repeater experiments — •Peter Gschwandtner, Quirin Buchinger, Constantin Krause, Sebastian Krüger, Silke Kuhn, Tobias Huber-Loyola, and Sven Höfling — Julius-Maximilian-Universität Würzburg, Physikalisches Institut, Lehrstuhl für Technische Physik, Germany

Semiconductor quantum dots (QD) are promising candidates for entangled photon sources (SPS) for quantum network purposes [1]. Single charge spins in QDs could serve as the quantum memory in the quantum repeater [2] or as a local entangler to create a photonic state for a memory-free quantum repeater [3 ].

In this talk, we present our experimental results for electrically contacted charge-tuneable p-i-n InAs QDs embedded in a circular Bragg grating (CBG). The cavity design enables us to control the charged exciton states of the quantum dots. The CBG exhibits high Purcell enhancement in a broad wavelength range. A novel labyrinth design of the CBG allows for electrical contacting without impeding other performance characteristics [4].

[1] D. Vajner et al., Adv. Quantum Technol. (2022), 10.1002/qute.202100116 [2] H.-J. Briegel, W. Dür, J. I. Cirac and P. Zoller, Phys. Rev. Lett. 81, 5932*5935 (1998), 10.1103/PhysRevLett.81.5932 [3] K. Azuma, K. Tamaki and H.-K. Lo, Nature communications 6, 6787 (2015)., 10.1038/ncomms7787 [4] Q. Buchinger et al., Appl. Physics Letters (2023), 10.1063/5.0136715

Keywords: Charge-tuneable quantum dots; Single Photon Source; Quantum Repeater; Molecular Beam Epitaxy