Near-field photon entanglement in total angular momentum

• 成果类型: Article
• 署名作者: Kam, Amit; Tsesses, Shai; Ilin, Yigal; Cohen, Kobi; Lumer, Yaakov; Fridman, Lior; Lotan, Stav; Patsyk, Anatoly; Nemirovsky-Levy, Liat; Orenstein, Meir; Segev, Mordechai; Bartal, Guy
• 署名单位: Technion Israel Institute of Technology; Technion Israel Institute of Technology; Massachusetts Institute of Technology (MIT); Massachusetts Institute of Technology (MIT); Technion Israel Institute of Technology
• 刊物名称: Nature
• ISSN/ISSBN: 0028-1536
• DOI: 10.1038/s41586-025-08761-1
• 发表日期: 2025-04-17
• 关键词: plasmon-assisted transmission; quantum entanglement; bessel beams; spin; generation; STATES; light

摘要

Photons can carry angular momentum, which is conventionally attributed to two constituents-spin angular momentum (SAM), which is an intrinsic property related to the polarization, and orbital angular momentum (OAM), which is related to the photon spatial distribution. In paraxial optics, these two forms of angular momentum are separable(1), such that entanglement can be induced between the SAM and the OAM of a single photon(2,3) or of different photons in a multi-photon state(4). In nanophotonic systems, however, the SAM and the OAM of a photon are inseparable(5,6), so only the total angular momentum (TAM) serves as a good quantum number(7), (8-9). Here we present the observation of non-classical correlations between two photons in the near-field regime, giving rise to entanglement related to the TAM. We entangle those nanophotonic states by coupling photon pairs to plasmonic modes and use quantum imaging techniques(10,11) to measure their correlations. We observe that entanglement in TAM leads to a completely different structure of quantum correlations of photon pairs, compared with entanglement related to the two constituent angular momenta. This work paves the way for on-chip quantum information processing using the TAM of photons as the encoding property for quantum information.