Mainz 2026 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 30: QuanTour III – Spin Physics & Coherence
Q 30.3: Vortrag
Mittwoch, 4. März 2026, 15:15–15:30, P 1
Modeling coherent Faraday spin control in semiconductor quantum dots — •Jan M. Kaspari1, Zhe Xian Koong2, Dorian Gangloff2, and Doris E. Reiter1 — 1TU Dortmund, Dortmund, Germany — 2University of Cambridge, Cambridge, United Kingdom
Semiconductor quantum dots (QDs) not only offer exceptional optical coherence and efficiency when coupled to photonic structures but also exhibit remarkably long electronic and nuclear spin coherence times, which makes them stand out as promising building blocks for memory-assisted quantum network protocols.
However, these schemes require both the ability to encode information via quantum control over the spin and the possibility to perform single-shot readouts.
While spin control in QDs is possible by applying an in-plane magnetic field (Voigt configuration), attempts to overcome the limitations given by the lack of intrinsically cyclic transitions to realize simultaneous single-shot readouts have shown limited success.
In the presence of a magnetic field oriented along the growth-axis of the quantum dot (Faraday geometry) circularly polarized cyclic transitions allow for efficient single-shot readouts. Here, we show that electron-spin resonance can be driven and quantum control over the spin can be achieved using a narrowband stimulated Raman scheme exploiting the small light-hole admixture. This slightly breaks the full cyclicity and leads to a highly asymmetric Λ system, which our theoretical model reproduces in excellent agreement with experiment [1].
[1] Zhe Xian Koong et al., arXiv:2509.14445 (2025)
Keywords: spin control; quantum dot; electron spin resonance; theory