Full-field mapping of spatially varying polarization entanglement generated from spontaneous parametric down-conversion

Abstract:Two-photon states generated from spontaneous parametric down-conversion (SPDC) can display entanglement in all degrees of freedom (DoFs) of light, including spatial, temporal, and polarization. The coupling between different DoFs of a two-photon state has been shown to display rich structures that enable novel and robust information processing schemes. While existing literature has studied these couplings by post-selecting the SPDC field, a comprehensive understanding of the inherent spatial-polarization coupling produced in the SPDC process is still lacking. This work produces a full spatial map of the polarization entanglement generated across the entire SPDC field, which contains an entire class of near-maximally polarization-entangled states with an average concurrence of 0.8303 +/- 0.0004. The spatial-polarization coupling manifests as radially or linearly varying polarization-entangled states, whose wavefunctions are dependent on the transverse momenta of the down-converted photons and the pump beam, respectively. Our study lays important groundwork for further exploiting the coupling between entanglement in different DoFs for future quantum technologies

Quantum Physics (quant-ph); Optics (physics.optics)

arXiv:2502.03586 [quant-ph]

(or arXiv:2502.03586v4 [quant-ph] for this version)

https://doi.org/10.48550/arXiv.2502.03586 Focus to learn more arXiv-issued DOI via DataCite

https://doi.org/10.1103/l9vh-14nj Focus to learn more DOI(s) linking to related resources

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