Room-temperature on-chip orbital angular momentum single-photon sources.

Wu, Cuo; Kumar, Shailesh; Kan, Yinhui; Komisar, Danylo; Wang, Zhiming; Bozhevolnyi, Sergey I; Ding, Fei · Sci Adv · 2022

basic_science · Level V

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Abstract

On-chip photon sources carrying orbital angular momentum (OAM) are in demand for high-capacity optical information processing in both classical and quantum regimes. However, currently exploited integrated OAM sources have been primarily limited to the classical regime. Here, we demonstrate a room-temperature on-chip integrated OAM source that emits well-collimated single photons, with a single-photon purity of <i>g</i><sup>(2)</sup>(0) ≈ 0.22, carrying entangled spin and OAM states and forming two spatially separated entangled radiation channels with different polarization properties. The OAM-encoded single photons are generated by efficiently outcoupling diverging surface plasmon polaritons excited with a deterministically positioned quantum emitter via Archimedean spiral gratings. Our OAM single-photon source platform bridges the gap between conventional OAM manipulation and nonclassical light sources, enabling high-dimensional and large-scale photonic quantum systems for quantum information processing.