Advancing the heralded photon-number-state characterization by understanding the interplay of experimental settings

TL;DR

This paper theoretically analyzes heralded photon-number states, focusing on how experimental parameters affect state quality, and introduces photon-number parity as a practical tool for assessing state purity in quantum optics.

Contribution

It provides a detailed theoretical framework linking experimental parameters to the quality of heralded photon-number states, highlighting photon-number parity as a robust assessment method.

Findings

Photon-number parity effectively indicates state contamination.

Optimal parameter regions for high-quality state generation are identified.

Results are expressed in terms of accessible experimental parameters.

Abstract

We theoretically explore the properties of heralded number states including up to three photons that are generated from single-mode twin beams. We investigate the effects of different parameters involved in the state preparation by using the fidelity, normalized second-order factorial moment of photon number for the heralded state $(g^{(2)}_h)$, and photon-number parity as figures of merit. Especially, the photon-number parity offers a practical and robust tool for inferring the target state quality by capturing the contamination of all undesired photon-number contributions. We focus on expressing our results in terms of experimentally easily accessible parameters such as the coincidences-to-accidentals ratio and the detection efficiencies. Our results identify the optimal parameter regions for generating high quality photon-number states by heralding and provide useful insights for advancing their use in quantum technologies.