Hyperentanglement in structured quantum light
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 polarization 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 characterize via two-photon interference and quantum state tomography, achieving near-unity visibilities and fidelities. While hyperentanglement has been demonstrated before in photonic qubits, here we present a rich entanglement structure involving spectrally and spatially structured light, where three different forms of entanglement coexist in the same biphoton state.
- Publication:
-
Physical Review Research
- Pub Date:
- December 2020
- DOI:
- 10.1103/PhysRevResearch.2.043350
- arXiv:
- arXiv:2006.01845
- Bibcode:
- 2020PhRvR...2d3350G
- Keywords:
-
- Quantum Physics;
- Physics - Optics
- E-Print:
- 5 pages, 4 figures, Supplement: 6 pages, 2 figures