Transmission of Photonic Quantum Polarization Entanglement in a Nanoscale Hybrid Plasmonic Waveguide

TL;DR

This paper demonstrates the preservation of quantum polarization entanglement in a nanoscale hybrid plasmonic waveguide, bridging nanophotonics and quantum optics with potential for high-resolution quantum sensing.

Contribution

First experimental demonstration of maintaining quantum polarization entanglement in a nanoscale hybrid plasmonic waveguide.

Findings

Fidelity of 0.932 with maximally entangled state

Violation of CHSH inequality with value 2.495

Potential application as a near-field quantum probe

Abstract

Photonic quantum technologies have been extensively studied in quantum information science, owing to the high-speed transmission and outstanding low-noise properties of photons. However, applications based on photonic entanglement are restricted due to the diffraction limit. In this work, we demonstrate for the first time the maintaining of quantum polarization entanglement in a nanoscale hybrid plasmonic waveguide composed of a fiber taper and a silver nanowire. The transmitted state throughout the waveguide has a fidelity of 0.932 with the maximally polarization entangled state {\Phi}+. Furthermore, the Clauser, Horne, Shimony, and Holt (CHSH) inequality test performed, resulting in value of 2.495+/-0.147 > 2, demonstrates the violation of the hidden variable model. Because the plasmonic waveguide confines the effective mode area to subwavelength scale, it can bridge nanophotonics and quantum optics and may be used as near-field quantum probe in a quantum near-field micro/nanoscope, which can realize high spatial resolution, ultrasensitive, fiber-integrated, and plasmon-enhanced detection.