Mode structure reconstruction by detected and undetected light

TL;DR

This paper presents a new method for reconstructing multimode optical fields using both correlation functions and anti-correlation functions, improving accuracy and noise resilience in quantum optical measurements.

Contribution

The authors introduce a novel reconstruction technique combining $g^{(K)}$ and $ heta^{(K)}$ functions, enhancing fidelity and reducing prior information needed.

Findings

Higher fidelity in mode reconstruction compared to existing methods

Effective in noisy environments with background light

Applicable to quantum information and metrology

Abstract

We introduce a novel technique for the reconstruction of multimode optical fields, based on simultaneously exploiting both the generalized Glauber's $K^{th}$-order correlation function $g^{(K)}$ and a recently proposed anti-correlation function (dubbed $\theta^{(K)}$) which is resilient to Poissonian noise. We experimentally demonstrate that this method yields mode reconstructions with higher fidelity with respect to those obtained with reconstruction methods based only on $g^{(K)}$'s, even requiring less "a priori" information. The reliability and versatility of our technique make it suitable for a widespread use in real applications of optical quantum measurement, from quantum information to quantum metrology, especially when one needs to characterize ensembles of single-photon emitters in the presence of background noise (due, for example, to residual excitation laser, stray light, or unwanted fluorescence).