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Frontiers in Optics

Entanglement between photons that never co-existed

E. Megidish, A. Halevy, Tomer Shacham, Tom Dvir, Liat Dovrat, H. S. Eisenberg

Published Jan 1, 2012• 4 citations
Publisher

Abstract

We entangle two photons, with the first detected even before the other is created, by using entanglement swapping between temporally-separated polarization-entangled photon pairs. This result shows the nonlocality of quantum mechanics in spacetime.
DOI
10.1364/fio.2012.fth2c.4

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Entanglement swapping at 1550 nm was experimentally demonstrated based on two polarization‐entangled photon pairs, which were created in two independent PPLN waveguides. Mandel dip was measured by using fourfold coincidences to yield a visibility of 71.8% and verify quantum interference between photons from two separated sources. By making Bell‐state measurement, the two initially independent photons were projected into an entanglement state. An interference visibility of 37.5% was observed for these two photons indicating the entanglement state was successfully swapped by using polarization‐entangled photon pairs in the telecom band.