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arXiv · 1206.3051

Interfacing a quantum dot spin with a photonic circuit

Isaac J. Luxmoore·Nicholas A. Wasley·Andrew J. Ramsay·Arthur C. T. Thijssen·Ruth Oulton·Maxime Hugues·Sachin Kasture·Achanta V. Gopal·A. Mark Fox·Maurice S. Skolnick
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Abstract

A scalable optical quantum information processor is likely to be a waveguide circuit with integrated sources, detectors, and either deterministic quantum-logic or quantum memory elements. With microsecond coherence times, ultrafast coherent control, and lifetime-limited transitions, semiconductor quantum-dot spins are a natural choice for the static qubits. However their integration with flying photonic qubits requires an on-chip spin-photon interface, which presents a fundamental problem: the spin-state is measured and controlled via circularly-polarised photons, but waveguides support only linear polarisation. We demonstrate here a solution based on two orthogonal photonic nanowires, in which the spin-state is mapped to a path-encoded photon, thus providing a blue-print for a scalable spin-photon network. Furthermore, for some devices we observe that the circular polarisation state is directly mapped to orthogonal nanowires. This result, which is physically surprising for a non-chiral structure, is shown to be related to the nano-positioning of the quantum-dot with respect to the photonic circuit.

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Isaac J. Luxmoore, Nicholas A. Wasley, Andrew J. Ramsay, Arthur C. T. Thijssen, Ruth Oulton, Maxime Hugues, Sachin Kasture, Achanta V. Gopal, A. Mark Fox, Maurice S. Skolnick. 2012-06-14. Interfacing a quantum dot spin with a photonic circuit. https://doi.org/10.1103/physrevlett.110.037402

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