Berlin 2024 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 37: Poster IV

HL 37.7: Poster

Wednesday, March 20, 2024, 18:00–20:30, Poster F

Deterministically fabricated wavelength-tunable quantum dot device for interfacing with atomic vapor-based quantum memory — •Avijit Barua¹, Ching-Wen Shih¹, Yuhui Yang¹, Chirag C. Palekar¹, Lucas Rickert¹, Benjamin Maass², Norman V. Ewald², Jin-Dong Song³, Janik Wolters², and Stephan Reitzenstein¹ — ¹Technische Universität Berlin, Hardenbergstr. 36, Berlin, Germany — ²German Aerospace Center (DLR), Rutherfordstr. 2, Berlin, Germany — ³Korea Institute of Science and Technology, Seoul, Republic of Korea

Semiconductor quantum dots (QDs) are extensively investigated as single-photon sources for applications in photonic quantum technology. Here, we develop bright and strain-tunable semiconductor QD single-photon sources at the Cs-D1 transition wavelength (894.6 nm). The devices are designed and numerically optimized to maximize extraction efficiency using the finite element method. By considering circular Bragg resonators with integrated QDs and Au-backside mirror we theoretically expect a photon extraction efficiency over 90% and a Purcell factor of 0.07. In the device fabrication, we implement in-situ electron-beam lithography to integrate QDs with spatial precision as good as 20 nm to create bright single-photon sources. By means of photon autocorrelation measurements, we demonstrate single-photon purity up to 97%. Furthermore, we explore the prospects of interfacing the QD single photons with a room-temperature ladder-type atomic vapor-based memory that allows for low-noise storage and retrieval at high repetition rates.

Keywords: Circular Bragg gratings; Atomic memory; Hybrid system; In-situ Electron-beam lithography