Quantum plasmonic sensing using single photons

TL;DR

This paper demonstrates that quantum plasmonic sensors utilizing single photons can surpass shot-noise limits in refractive index estimation, showing promise for practical quantum sensing applications.

Contribution

The study introduces a quantum plasmonic sensing method using heralded single photons in a Kretschmann configuration, achieving sub shot-noise estimation errors.

Findings

Errors below shot-noise limit achieved with single photons

Sensor remains effective despite experimental imperfections

Practical quantum plasmonic sensing demonstrated

Abstract

Reducing the noise below the shot-noise limit in sensing devices is one of the key promises of quantum technologies. Here, we study quantum plasmonic sensing based on an attenuated total reflection configuration with single photons as input. Our sensor is the Kretschmann configuration with a gold film, and a blood protein in an aqueous solution with different concentrations serves as an analyte. The estimation of the refractive index is performed using heralded single photons. We also determine the estimation error from a statistical analysis over a number of repetitions of identical and independent experiments. We show that the errors of our plasmonic sensor with single photons are below the shot-noise limit even in the presence of various experimental imperfections. Our results demonstrate a practical application of quantum plasmonic sensing is possible given certain improvements are made to the setup investigated, and pave the way for a future generation of quantum plasmonic applications based on similar techniques.