Augmenting the Sensing Performance of Entangled Photon Pairs through Asymmetry

TL;DR

This paper investigates how asymmetry in detection, stimulation, and loss impacts the performance of quantum nonlinear interferometers with entangled photon pairs, revealing ways to enhance phase sensitivity and mitigate losses.

Contribution

It provides a theoretical and experimental analysis of asymmetry effects, showing how coherent seeding can improve loss tolerance and phase sensitivity in quantum interferometry.

Findings

Visibility distinguishes loss on signal vs. idler modes

Coherent seeding mitigates conjugated mode losses

Enhanced sub-shot-noise phase detection threshold

Abstract

We analyze theoretically and experimentally cases of asymmetric detection, stimulation, and loss within a quantum nonlinear interferometer of entangled pairs. We show that the visibility of the SU(1,1) interference directly discerns between loss on the measured mode (signal) and the conjugated mode (idler). This asymmetry also affects the phase sensitivity of the interferometer, where coherent seeding is shown to mitigate losses that are suffered by the conjugated mode; therefore increasing the maximum threshold of loss that permits sub-shot-noise phase detection. Our findings can improve the performance of setups that rely on direct detection of entangled pairs, such as quantum interferometry and imaging with undetected photons.