# Direct experimental observation of nonclassicality in ensembles of single photon emitters

## TL;DR

This paper experimentally demonstrates a new criterion to detect nonclassical light emission in ensembles of single-photon emitters, specifically NV centers in diamond, using a novel measurement approach.

## Contribution

It introduces and applies a recently proposed nonclassicality detection criterion to ensembles of emitters, advancing experimental methods in quantum optics.

## Key findings

- Successful experimental validation of the nonclassicality criterion
- Application to NV centers in diamond using confocal microscopy
- Discussion on detection of manifold coincidences and noise effects

## Abstract

In this work we experimentally demonstrate for the first time a recently proposed criterion adressed to detect nonclassical behavior in the fluorescence emission of ensembles of single-photon emitters. In particular, we apply the method to study clusters of NV centres in diamond observed via single-photon-sensitive confocal microscopy. Theoretical considerations on the behavior of the parameter at any arbitrary order in presence of poissonian noise are presented and, finally, the opportunity of detecting manifold coincidences is discussed.