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arXiv · 2504.20497

Initialization of Neutral and Charged Exciton Spin States in a Telecom-Emitting Quantum Dot

Giora Peniakov·Johannes Michl·Mohamed Helal·Raphael Joos·Michael Jetter·Simone L. Portalupi·Peter Michler·Sven Höfling·Tobias Huber-Loyola
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Abstract

Photonic cluster states are highly entangled states that allow for photonic quantum computing and memory-less quantum repeaters. Their generation has been recently demonstrated using semiconductor quantum dots emitting at the 900 nm wavelength range. However, a similar demonstration at the communication-optimal telecom range has remained elusive. A key ingredient that is still missing is an appropriate optical excitation method. A central requirement of such a method is to allow an arbitrary spin initialization of quantum dot excitonic complexes. In this work, we report on developing such a method based on a quasi-resonant p-shell excitation for a telecom-C-band-emitting quantum dot. We show qubit writing of a neutral exciton and spin-preserving excitation of a negative trion. Using the Larmor precession of the negative trion under an externally applied magnetic field, we determine the in-plane g-factors of both the electron and the hole in the investigated quantum dot. In addition, we measure a lower bound on the hole coherence time, $T_{2}^{*}>6.4$ ns, boosting its candidacy as a sound photon entangler for more advanced quantum photonic schemes.

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Giora Peniakov, Johannes Michl, Mohamed Helal, Raphael Joos, Michael Jetter, Simone L. Portalupi, Peter Michler, Sven Höfling, Tobias Huber-Loyola. 2025-04-29. Initialization of Neutral and Charged Exciton Spin States in a Telecom-Emitting Quantum Dot. https://doi.org/10.1103/3qh7-b696

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