Multiparameter estimation theory offers a general framework to explore imaging techniques beyond the Rayleigh limit. While optimal measurements of single parameters characterizing a composite light source are now well understood, simultaneous determination of multiple parameters poses a much greater challenge that in general requires implementation of collective measurements. Here we show, theoretically and experimentally, that Hong-Ou-Mandel interference followed by spatially resolved detection of photons provides precise information on both the separation and the centroid for a pair of point emitters, avoiding trade-offs inherent to single-photon measurements.
@article{arxiv.1803.07096,
title = {Beating the Rayleigh Limit Using Two-Photon Interference},
author = {Michał Parniak and Sebastian Borówka and Kajetan Boroszko and Wojciech Wasilewski and Konrad Banaszek and Rafał Demkowicz-Dobrzański},
journal= {arXiv preprint arXiv:1803.07096},
year = {2018}
}