Science Daily February 25, 2019
A team of researchers in the US (NIST, University of Maryland) created quantum-correlated pairs made up of one visible and one near-infrared photon. The visible-light partners can interact with trapped atoms, ions, or other systems that serve as quantum versions of computer memory while the near-infrared members of each couple are free to propagate over long distances through the optical fiber. The design methods can be easily applied to create many other visible-light/near-infrared pairs tailored to match specific systems of interest. In the future, by combining two of the entangled pairs with two quantum memories, the entanglement inherent in the photon pairs can be transferred to the quantum memories. This technique called entanglement swapping, allows the memories to be entangled with each other over a much longer distance than would normally be possible…read more. TECHNICAL ARTICLEÂ
Light from a pump laser (purple regions in the resonator) generates one photon in each pair at a visible-light wavelength (red patches in and around resonator). Credit: S. Kelley/NIST