Pure down-conversion photons through sub-coherence-length domain engineering. (12th July 2017)

• Record Type: Journal Article
• Authors: Graffitti, Francesco; Kundys, Dmytro; Reid, Derryck T; Brańczyk, Agata M; Fedrizzi, Alessandro
• Is Part Of: Quantum science and technology. Volume 2:Number 3(2017)
• Publication Date: 2017-07-12
• Subjects: entanglement -- nonlinear processes -- single photon sources -- quantum optics -- parametric down conversion -- quantum information; Quantum theory -- Periodicals; Quantum theory; Periodicals; 530
• DOI: 10.1088/2058-9565/aa78d4
• Languages: English
• ISSNs: 2058-9565

Abstract

Abstract: Photonic quantum technology relies on efficient sources of coherent single photons, the ideal carriers of quantum information. Heralded single photons from parametric down-conversion can approximate on-demand single photons to a desired degree, with high spectral purities achieved through group-velocity matching and tailored crystal nonlinearities. Here we propose crystal-nonlinearity-engineering techniques with sub-coherence-length domains. We first introduce a combination of two existing methods: a deterministic approach with coherence-length domains and probabilistic domain-width annealing. We then show how the same deterministic domain-flip approach can be implemented with sub-coherence-length domains. Both of these complementary techniques create highly pure photons, outperforming previous methods, in particular for short nonlinear crystals matched to femtosecond lasers.