Bright nanoscale source of deterministic entangled photon pairs violating Bell's inequality

Bright nanoscale source of deterministic entangled photon pairs violating Bell's inequality

Jöns, K.D. (TU Delft QN/Quantum Nanoscience; AlbaNova University Center; Kavli institute of nanoscience Delft)
Schweickert, L.S. (TU Delft QN/Zwiller Lab; AlbaNova University Center; Kavli institute of nanoscience Delft)
Versteegh, M.A.M. (TU Delft QN/Quantum Transport; AlbaNova University Center; University of Vienna; Austrian Academy of Sciences; Kavli institute of nanoscience Delft)
Dalacu, Dan (National Research Council Canada)
Poole, Philip J. (National Research Council Canada)
Gulinatti, Angelo (Politecnico di Milano)
Giudice, Andrea (Micro Photon Devices)
Zwiller, V.G. (TU Delft QN/Zwiller Lab; AlbaNova University Center; Kavli institute of nanoscience Delft)
Reimer, M.E. (TU Delft QN/Quantum Transport; University of Waterloo; Kavli institute of nanoscience Delft)

QN/Quantum Nanoscience

2017-12-01

Global, secure quantum channels will require efficient distribution of entangled photons. Long distance, low-loss interconnects can only be realized using photons as quantum information carriers. However, a quantum light source combining both high qubit fidelity and on-demand bright emission has proven elusive. Here, we show a bright photonic nanostructure generating polarization-entangled photon pairs that strongly violates Bell's inequality. A highly symmetric InAsP quantum dot generating entangled photons is encapsulated in a tapered nanowire waveguide to ensure directional emission and efficient light extraction. We collect ∼200 kHz entangled photon pairs at the first lens under 80 MHz pulsed excitation, which is a 20 times enhancement as compared to a bare quantum dot without a photonic nanostructure. The performed Bell test using the Clauser-Horne-Shimony-Holt inequality reveals a clear violation (S _CHSH > 2) by up to 9.3 standard deviations. By using a novel quasi-resonant excitation scheme at the wurtzite InP nanowire resonance to reduce multi-photon emission, the entanglement fidelity (F = 0.817 ± 0.002) is further enhanced without temporal post-selection, allowing for the violation of Bell's inequality in the rectilinear-circular basis by 25 standard deviations. Our results on nanowire-based quantum light sources highlight their potential application in secure data communication utilizing measurement-device-independent quantum key distribution and quantum repeater protocols.

http://resolver.tudelft.nl/uuid:9cd5c272-1362-4dce-ac14-dbe2dd82d79e

https://doi.org/10.1038/s41598-017-01509-6

2045-2322

Scientific Reports, 7 (1)

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© 2017 K.D. Jöns, L.S. Schweickert, M.A.M. Versteegh, Dan Dalacu, Philip J. Poole, Angelo Gulinatti, Andrea Giudice, V.G. Zwiller, M.E. Reimer