# Criteria for single photon sources with variable nonclassicality threshold

## TL;DR

This paper introduces a hierarchy of adjustable experimental criteria to evaluate and compare the nonclassicality of single photon sources, enhancing the assessment of their suitability for quantum technologies.

## Contribution

It proposes a novel, adjustable set of nonclassicality criteria using linear optical networks, surpassing traditional tests like photon antibunching.

## Key findings

- Hierarchy of nonclassicality criteria established
- Allows faithful comparison of single-photon source quality
- Enables tailored testing for different quantum applications

## Abstract

Single photon sources are necessary for optical quantum technology. The nonclassicality of emitted single photons manifests itself in diverse experiments and applications. The applications already require different nonclassical aspects of single photons, however, a suitable hierarchy of criteria is missing. We propose variable experimental tests, based on adjustable linear optical networks and single photon detectors, giving a hierarchy of such nonclassicality criteria. The hierarchy goes beyond Hanbury - Brown - Twiss test of photon antibunching and allows us to compare faithfully quality and performance of single-photon sources via their nonclassical properties.