© 2026 Aqora Quantum S.A.S.

Terms Privacy Legal Notice

Superconductivity

Geometric origin of intrinsic dark counts in superconducting nanowire single-photon detectors

Xingyu Zhang, Xiaofu Zhang, Jia Huang, Can Hui Yang, Lixing You, Xiaoyu Liu, Peng Hu, You Xiao, Wenying Zhang, Yongliang Wang, Lingyun Li, Zhen Wang, Hao Li

Published Mar 1, 2022• 15 citations

Abstract

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.

DOI: 10.1016/j.supcon.2022.100006

Related papers

Characterization of superconducting nanowire single-photon detector with artificial constrictions

Ling Zhang, Lixing You, Dengkuan Liu +8 more

Statistical studies on the performance of different superconducting nanowire single-photon detectors (SNSPDs) on one chip suggested that random constrictions existed in the nanowire that were barely registered by scanning electron microscopy. With the aid of advanced e-beam lithography, artificial geometric constrictions were fabricated on SNSPDs as well as single nanowires. In this way, we studied the influence of artificial constrictions on SNSPDs in a straight forward manner. By introducing artificial constrictions with different wire widths in single nanowires, we concluded that the dark counts of SNSPDs originate from a single constriction. Further introducing artificial constrictions in SNSPDs, we studied the relationship between detection efficiency and kinetic inductance and the bias current, confirming the hypothesis that constrictions exist in SNSPDs.

arXiv:1406.2043•AIP Advances•Jun 1, 2014•15 citations

Dark counts of superconducting nanowire single-photon detector under illumination

Sijing Chen, Lixing You, Weijun Zhang +5 more

An abnormal increase in the SDE was observed for superconducting nanowire single-photon detectors (SNSPDs) when the bias current (I(b)) was close to the switching current (I(sw)). By introducing the time-correlated single-photon counting technique, we investigated the temporal histogram of the detection counts of an SNSPD under illumination. The temporal information helps us to distinguish photon counts from dark counts in the time domain. In this manner, the dark count rate (DCR) under illumination and the accurate SDE can be determined. The DCR under moderate illumination may be significantly larger than the conventional DCR measured without illumination under a high I(b), which causes the abnormal increase in the SDE. The increased DCR may be explained by the suppression of I(sw) under illumination.

arXiv:1504.04713•Optics Express•Apr 17, 2015•30 citations

Dark counts double switching rates in NbTiN Superconducting Nanowire Single Photon Detectors

Daniela Salvoni, Mikkel Ejrnaes, L. Parlato +5 more

Abstract In this work we present a study of the dark counts rate in a NbTiN Superconducting Nanowire Single Photon Detectors (SNSPD). We measure the distribution of the time intervals elapsed between two consecutive dark pulses at the fixed temperature of 4,2K. Due to the stochastic nature of the dark counts, the distribution is expected to have a Poisson shape but what we observe is a combination of two Poisson-like processes. A further analysis of the distributions dependence on the bias current highlights that the weight of the two process is not constant. In the scenario presented by Ejrnaes et al. [1], this result can confirm that, in this temperature regime, dark counts are generated mainly by multiple consecutive fluctuation events and the contribution to the dark counts rate coming from single fluctuations increases in the high bias current region.

Journal of Physics Conference Series•Jun 1, 2020•0 citations

Waveform analysis of a large-area superconducting nanowire single photon detector

Claire E. Marvinney, Brian Lerner, Alexander A Puretzky +2 more

Abstract Superconducting nanowire single photon detectors (SNSPDs) are typically used as single-mode-fiber-coupled single-pixel detectors, but large area detectors are increasingly critical for applications ranging from microscopy to free-space quantum communications. However, the long meander-line length of such large-area SNSPDs results in a proportionately large kinetic inductance that affects the waveform generated by the device. Here, we explore changes in the rising edge of the readout pulse for a single-pixel large-area SNSPD as a function of the optical spot size on the detector and compare to the rising edge of the dark-count waveform. We observe a bimodal distribution of bright-count rise times and show that the probability of a slow rise time increases in the limit of large spot sizes, indicative of a position sensitive response. Additionally, in the limit of low bias currents, the dark-count readout pulse is most similar to the large spot-size bright-count readout pulse, which suggests that dark counts arise from locations spanning the device. These results are consistent with a simple model of traveling microwave modes excited by single photons incident at varying positions along the length of the nanowire.

arXiv:2006.00126•Superconductor Science and Technology•Dec 7, 2020•7 citations

Origin of intrinsic dark count in superconducting nanowire single-photon detectors

Taro Yamashita, A S. Miki, Kazumasa Makise +4 more

The origin of the decoherence in superconducting nanowire single-photon detectors, the so-called dark count, was investigated. We measured the direct-current characteristics and bias-current dependencies of the dark count rate in a wide range of temperatures from 0.5 K to 4.0 K, and analyzed the results by theoretical models of thermal fluctuations of vortices. Our results indicate that the current-assisted unbinding of vortex-antivortex pairs is the dominant origin of the dark count.

•Jan 1, 2013•47 citations

Origin of intrinsic dark count in superconducting nanowire single-photon detectors

T. Yamashita, S. Miki, K. Makise +5 more

The origin of the decoherence in superconducting nanowire single-photon detectors, the so-called dark count, was investigated. We measured the direct-current characteristics and bias-current dependencies of the dark count rate in a wide range of temperatures from 0.5 K to 4.0 K, and analyzed the results by theoretical models of thermal fluctuations of vortices. Our results indicate that the current-assisted unbinding of vortex-antivortex pairs is the dominant origin of the dark count.

arXiv:1103.2844•Applied Physics Letters•Oct 17, 2011•77 citations

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.

Statistical studies on the performance of different superconducting nanowire single-photon detectors (SNSPDs) on one chip suggested that random constrictions existed in the nanowire that were barely registered by scanning electron microscopy. With the aid of advanced e-beam lithography, artificial geometric constrictions were fabricated on SNSPDs as well as single nanowires. In this way, we studied the influence of artificial constrictions on SNSPDs in a straight forward manner. By introducing artificial constrictions with different wire widths in single nanowires, we concluded that the dark counts of SNSPDs originate from a single constriction. Further introducing artificial constrictions in SNSPDs, we studied the relationship between detection efficiency and kinetic inductance and the bias current, confirming the hypothesis that constrictions exist in SNSPDs.

An abnormal increase in the SDE was observed for superconducting nanowire single-photon detectors (SNSPDs) when the bias current (I(b)) was close to the switching current (I(sw)). By introducing the time-correlated single-photon counting technique, we investigated the temporal histogram of the detection counts of an SNSPD under illumination. The temporal information helps us to distinguish photon counts from dark counts in the time domain. In this manner, the dark count rate (DCR) under illumination and the accurate SDE can be determined. The DCR under moderate illumination may be significantly larger than the conventional DCR measured without illumination under a high I(b), which causes the abnormal increase in the SDE. The increased DCR may be explained by the suppression of I(sw) under illumination.

Abstract In this work we present a study of the dark counts rate in a NbTiN Superconducting Nanowire Single Photon Detectors (SNSPD). We measure the distribution of the time intervals elapsed between two consecutive dark pulses at the fixed temperature of 4,2K. Due to the stochastic nature of the dark counts, the distribution is expected to have a Poisson shape but what we observe is a combination of two Poisson-like processes. A further analysis of the distributions dependence on the bias current highlights that the weight of the two process is not constant. In the scenario presented by Ejrnaes et al. [1], this result can confirm that, in this temperature regime, dark counts are generated mainly by multiple consecutive fluctuation events and the contribution to the dark counts rate coming from single fluctuations increases in the high bias current region.

Abstract Superconducting nanowire single photon detectors (SNSPDs) are typically used as single-mode-fiber-coupled single-pixel detectors, but large area detectors are increasingly critical for applications ranging from microscopy to free-space quantum communications. However, the long meander-line length of such large-area SNSPDs results in a proportionately large kinetic inductance that affects the waveform generated by the device. Here, we explore changes in the rising edge of the readout pulse for a single-pixel large-area SNSPD as a function of the optical spot size on the detector and compare to the rising edge of the dark-count waveform. We observe a bimodal distribution of bright-count rise times and show that the probability of a slow rise time increases in the limit of large spot sizes, indicative of a position sensitive response. Additionally, in the limit of low bias currents, the dark-count readout pulse is most similar to the large spot-size bright-count readout pulse, which suggests that dark counts arise from locations spanning the device. These results are consistent with a simple model of traveling microwave modes excited by single photons incident at varying positions along the length of the nanowire.