Optics Express
Modified detector tomography technique applied to a superconducting multiphoton nanodetector
J. J. Renema, G. Frucci, Zhiping Zhou, F. Mattioli, Alessandro Gaggero, Roberto Leoni, M. J. A. de Dood, Andrea Fiore, Martin P. van Exter
Abstract
We present an experimental method to characterize multi-photon detectors with a small overall detection efficiency. We do this by separating the nonlinear action of the multiphoton detection event from linear losses in the detector. Such a characterization is a necessary step for quantum information protocols with single and multiphoton detectors and can provide quantitative information to understand the underlying physics of a given detector. This characterization is applied to a superconducting multiphoton nanodetector, consisting of an NbN nanowire with a bowtie-shaped subwavelength constriction. Depending on the bias current, this detector has regimes with single and multiphoton sensitivity. We present the first full experimental characterization of such a detector.