Double-heralded generation of two-photon-states by spontaneous four-wave-mixing in the presence of noise

TL;DR

This paper introduces an experimental approach to generate and verify photon-number states using spontaneous four-wave-mixing, addressing noise effects and proposing methods to characterize and mitigate noise in heralded photon experiments.

Contribution

It presents a novel method for creating and verifying photon-number states with noise analysis and noise mitigation techniques in heralded four-wave-mixing sources.

Findings

Noise photons significantly degrade two-photon state heralding

A method to characterize and estimate noise-free photon-number distribution is demonstrated

Equivalence between noise in herald channel and loss in signal channel is established

Abstract

We present an experimental method for creating and verifying photon-number states created by non-degenerate, third-order nonlinear-optical photon-pair sources. By using spatially multiplexed, thresholding single-photon detectors and inverting a conditional probability matrix, we determine the photon-number probabilities created through heralded spontaneous four-wave-mixing. The deleterious effects of noise photons on reliable heralding are investigated and shown to degrade the conditional preparation of two-photon number states more than they degrade conditional single-photon states. We derive the equivalence between the presence of unwanted noise in the herald channel and loss in the signal channel of heralded experiments. A procedure for characterizing the noise-photon contributions, and a means of estimating the herald noise-free photon-number distribution is demonstrated.