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. Herein, we demonstrate a room-temperature on-chip integrated OAM source that emits well-collimated single photons, with a single-photon purity of g(2)(0) = 0.22, carrying entangled spin and orbital angular momentum 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 sources bridge the gap between conventional OAM manipulation and nonclassical light sources, enabling high-dimensional and large-scale photonic quantum systems for information processing.
@article{arxiv.2104.01118,
title = {Room-temperature on-chip orbital angular momentum single-photon sources},
author = {Cuo Wu and Shailesh Kumar and Yinhui Kan and Danylo Komisar and Zhiming Wang and Sergey I. Bozhevolnyi and Fei Ding},
journal= {arXiv preprint arXiv:2104.01118},
year = {2022}
}