Spectral Sensitivity of the NbN Single-Photon Superconducting Detector

Roman SOBOLEWSKI  Ying XU  Xuemei ZHENG  Carlo WILLIAMS  Jin ZHANG  Aleksandr VEREVKIN  Galina CHULKOVA  Alexander KORNEEV  Andrey LIPATOV  Oleg OKUNEV  Konstantin SMIRNOV  Gregory N. GOL'TSMAN  

IEICE TRANSACTIONS on Electronics   Vol.E85-C    No.3    pp.797-802
Publication Date: 2002/03/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section INVITED PAPER (Special Issue on Superconductive Electronics)
Category: Novel Devices and Device Physics
single-photon optical detector,  quantum efficiency,  infrared radiation,  NbN superconducting thin film,  quantum communication,  spectral sensitivity,  

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We report our studies on the spectral sensitivity of superconducting NbN thin-film single-photon detectors (SPD's) capable of GHz counting rates of visible and near-infrared photons. In particular, it has been shown that a NbN SPD is sensitive to 1.55-µm wavelength radiation and can be used for quantum communication. Our SPD's exhibit experimentally measured intrinsic quantum efficiencies from 20% at 800 nm up to 1% at 1.55-µm wavelength. The devices demonstrate picosecond response time (<100 ps, limited by our readout system) and negligibly low dark counts. Spectral dependencies of photon counting of continuous-wave, 0.4-µm to 3.5-µm radiation, and 0.63-µm, 1.33-µm, and 1.55-µm laser-pulsed radiations are presented for the single-stripe-type and meander-type devices.