title: Local detection efficiency of a NbN superconducting single photon detector explored by a scattering scanning near-field optical microscope.
abstract: We propose an experiment to directly probe the local response of a superconducting single photon detector using a sharp metal tip in a scattering scanning near-field optical microscope. The optical absorption is obtained by simulating the tip-detector system, where the tip-detector is illuminated from the side, with the tip functioning as an optical antenna. The local detection efficiency is calculated by considering the recently introduced position-dependent threshold current in the detector. The calculated response for a 150 nm wide detector shows a peak close to the edge that can be spatially resolved with an estimated resolution of ∼ 20 nm, using a tip with parameters that are experimentally accessible.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Wang
authors.forename: Jelmer J
authors.initials: JJ
authors.lastname: Renema
authors.forename: Andreas
authors.initials: A
authors.lastname: Engel
authors.forename: Martin P
authors.initials: MP
authors.lastname: van Exter
authors.forename: Michiel J A
authors.initials: MJ
authors.lastname: de Dood