Quantum Imaging with Photon-Number Correlations

Non-classical correlations in optical beams offer the unprecedented opportunity of surpassing conventional limits of sensitivity and resolution in optical measurements and imaging, especially but not only, when a low photon flux down/single photons are measured. We review the principles quantum imaging and sensing techniques presenting some state-of-the-art achievements in the field. These quantum protocols have the potential to trigger major steps in many application ranging from radiometry to biophotonics.