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arXiv · 2006.01845

Hyperentanglement in structured quantum light

Francesco Graffitti·Vincenzo D'Ambrosio·Massimiliano Proietti·Joseph Ho·Bruno Piccirillo·Corrado de Lisio·Lorenzo Marrucci·Alessandro Fedrizzi
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Abstract

Entanglement in high-dimensional quantum systems, where one or more degrees of freedom of light are involved, offers increased information capacities and enables new quantum protocols. Here, we demonstrate a functional source of high-dimensional, noise-resilient hyperentangled states encoded in time-frequency and vector-vortex structured modes, which in turn carry single-particle entanglement between polarisation and orbital angular momentum. Pairing nonlinearity-engineered parametric downconversion in an interferometric scheme with spin-to-orbital-angular-momentum conversion, we generate highly entangled photon pairs at telecom wavelength that we characterise via two-photon interference and quantum state tomography, achieving near-unity visibilities and fidelities. While hyperentanglement has been demonstrated before in photonic qubits, this is the first instance of such a rich entanglement structure involving spectrally and spatially structured light, where three different forms of entanglement coexist in the same biphoton state.

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Francesco Graffitti, Vincenzo D'Ambrosio, Massimiliano Proietti, Joseph Ho, Bruno Piccirillo, Corrado de Lisio, Lorenzo Marrucci, Alessandro Fedrizzi. 2020-06-02. Hyperentanglement in structured quantum light. https://doi.org/10.1103/physrevresearch.2.043350

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