Clearer visibility Hong-Ou-Mandel effect with correlation function based on rates rather than intensities

TL;DR

This paper demonstrates that using correlation functions based on detection rates instead of intensities enhances the visibility of the Hong-Ou-Mandel effect, revealing non-classical features at higher pump powers in quantum optics experiments.

Contribution

The study introduces a rate-based correlation function approach that improves detection of non-classicality in quantum optical fields with undefined photon numbers, surpassing traditional intensity-based methods.

Findings

Higher non-classical visibilities observed beyond 1/2 at increased pump rates

Rate-based correlation functions outperform intensity-based ones in revealing non-classicality

Effective even with multiple pairs production due to stimulated emission

Abstract

We test ideas put forward e.g in arXiv:1508.02368, which suggest that using rates in quantum optics can lead to better indicators of non-classicality for states of quantum optical fields with undefined photon numbers. By rate we mean the ratio of registered photons in a given detector to the total number of detected photons in all detectors in the experiment. For the Hong-Ou-Mandel effect for parametric down conversion fields, we show that by using two detector correlation functions which are defined in terms of averages of products of measured rates, rather than usual intensities, one can observe non -- classical visibilities beyond $1/2$ for significantly higher pump rates. At such rates we already have a partially stimulated emission which leads to significant amplitudes for multiple pairs production, still the new approach allows to clearly see the non-classical dip.