The dark count is one of the key physical issues for superconducting nanowire single-photon detectors(SNSPDs)that limits various applications for optical quantum information and classical optics.When the bias current ...The dark count is one of the key physical issues for superconducting nanowire single-photon detectors(SNSPDs)that limits various applications for optical quantum information and classical optics.When the bias current approaches the switching current of SNSPDs,the dark count is actually dominated by the intrinsic dark counts(iDCs).However,the origin of iDCs and its relation to constrictions remains unclear for practical SNSPDs.We herein systematically characterize the iDCs of the SNSPDs with and without artificial geometric constrictions by applying the differential readout method.For these devices with constrictions,we have observed distinct Gaussian distributions in the temporal distribution of iDCs,in which the time difference between the distributions is consistent with the geometric distance between constrictions,and the rates of iDCs produced by each constriction are in good agreement with constrictions'widths.With respect to practical SNSPDs,surprisingly,we also observe several Gaussian distributions in the temporal domain and it shows no significant dependence on the devices’sizes,demonstrating that the iDCs of SNSPDs are mainly dominated by a few specific constrictions.展开更多
基金the National Key R&D Program of China(2017YFA0304000)National Natural Science Foundation of China(Grant Nos.61971408 and 61827823)+2 种基金Shanghai Municipal Science and Technology Major Project(2019SHZDZX01)Shanghai Rising-Star Program(20QA1410900)the Youth Innovation Promotion Association of Chinese Academy of Sciences(2020241,2021230).
文摘The dark count is one of the key physical issues for superconducting nanowire single-photon detectors(SNSPDs)that limits various applications for optical quantum information and classical optics.When the bias current approaches the switching current of SNSPDs,the dark count is actually dominated by the intrinsic dark counts(iDCs).However,the origin of iDCs and its relation to constrictions remains unclear for practical SNSPDs.We herein systematically characterize the iDCs of the SNSPDs with and without artificial geometric constrictions by applying the differential readout method.For these devices with constrictions,we have observed distinct Gaussian distributions in the temporal distribution of iDCs,in which the time difference between the distributions is consistent with the geometric distance between constrictions,and the rates of iDCs produced by each constriction are in good agreement with constrictions'widths.With respect to practical SNSPDs,surprisingly,we also observe several Gaussian distributions in the temporal domain and it shows no significant dependence on the devices’sizes,demonstrating that the iDCs of SNSPDs are mainly dominated by a few specific constrictions.
