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arXiv · 2303.02763

Resonant two-laser spin-state spectroscopy of a negatively charged quantum dot-microcavity system with a cold permanent magnet

P. Steindl·T. van der Ent·H. van der Meer·J. A. Frey·J. Norman·J. E. Bowers·D. Bouwmeester·W. Löffler
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Abstract

A high-efficiency spin-photon interface is an essential piece of quantum hardware necessary for various quantum technologies. Self-assembled InGaAs quantum dots have excellent optical properties, if embedded into an optical micro-cavity they can show near-deterministic spin-photon entanglement and spin readout, but an external magnetic field is required to address the individual spin states, which usually is done using a superconducting magnet. Here, we show a compact cryogenically compatible SmCo magnet design that delivers 475 mT in-plane Voigt geometry magnetic field at 5 K, which is suitable to lift the energy degeneracy of the electron spin states and trion transitions of a single InGaAs quantum dot. This quantum dot is embedded in a birefringent high-finesse optical micro-cavity which enables efficient collection of single photons emitted by the quantum dot. We demonstrate spin-state manipulation by addressing the trion transitions with a single and two laser fields. The experimental data agrees well to our model which covers single- and two-laser cross-polarized resonance fluorescence, Purcell enhancement in a birefringent cavity, and variation of the laser powers.

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P. Steindl, T. van der Ent, H. van der Meer, J. A. Frey, J. Norman, J. E. Bowers, D. Bouwmeester, W. Löffler. 2023-03-05. Resonant two-laser spin-state spectroscopy of a negatively charged quantum dot-microcavity system with a cold permanent magnet. https://doi.org/10.1103/physrevapplied.20.014026

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