Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physical Review B

Effect of magnetic field on the photon detection in thin superconducting meander structures

R. Lusche, Alexej D. Semenov, Yu. P. Korneeva, Andrey Trifonov, Alexander A. Korneev, G. N. Gol'Tsman, Heinz‐Wilhelm Hübers

Published Mar 19, 2014• 21 citations
Publisher

Abstract

We have studied the influence of an externally applied magnetic field on the photon and dark count rates of meander-type niobium nitride superconducting nanowire single-photon detectors. Measurements have been performed at a temperature of 4.2 K, and magnetic fields up to 250 mT have been applied perpendicularly to the meander plane. While photon count rates are field independent at weak applied fields, they show a strong dependence at fields starting from approximately \ifmmode\pm\else\textpm\fi{}25 mT. This behavior, as well as the magnetic field dependence of the dark count rates, is in good agreement with the recent theoretical model of vortex-assisted photon detection and spontaneous vortex crossing in narrow superconducting lines. However, the local reduction of the superconducting free energy due to photon absorption, which is the fitting parameter in the model, increases much slower with the photon energy than the model predicts. Furthermore, changes in the free-energy during photon counts and dark counts depend differently on the current that flows through the meander. This indicates that photon counts and dark counts occur in different parts of the meander.

DOI
10.1103/physrevb.89.104513

Related papers

Dependence of count rate on magnetic field in superconducting thin-film TaN single-photon detectors

Andreas Engel, A. Schilling, K. Ilin +1 more

We have studied the magnetic-field dependence of both dark-count rates and photon-count rates in a superconducting nanowire single-photon detector made of TaN in external magnetic fields $|{\ensuremath{\mu}}_{0}H|<10$ mT perpendicular to the plane of the underlying meander structure and at $T=4$ K. The dark-count rates show a characteristic field dependence, which is asymmetric with respect to magnetic-field direction. The field and the current dependence of the dark counts can be quantitatively well explained if one assumes that the critical current is reduced to $\ensuremath{\approx}$$50%$ at the ${180}^{\ensuremath{\circ}}$ meander turns when compared to a straight strip, and the observed asymmetry can be modeled assuming that the turnarounds are not all strictly equal. Surprisingly, the photon-count rates do not show any significant field dependence, which seems to be at odds with existing detection models invoking vortex crossings.

arXiv:1206.4579•Physical Review B•Oct 22, 2012•35 citations

Vortex-assisted photon counts and their magnetic field dependence in single-photon superconducting detectors

Lev N. Bulaevskii, Matthias J. Graf, V. G. Kogan

We argue that photon counts in a superconducting nanowire single-photon detector (SNSPD) are caused by the transition from a current-biased metastable superconducting state to the normal state. Such a transition is triggered by vortices crossing the thin and narrow superconducting strip from one edge to another due to the Lorentz force. Detector counts in SNSPDs may be caused by three processes: (a) a single incident photon with sufficient energy to break enough Cooper pairs to create a normal-state belt across the entire width of the strip (direct photon count), (b) thermally induced single-vortex crossing in the absence of photons (dark count), which at high-bias currents releases the energy sufficient to trigger the transition to the normal state in a belt across the whole width of the strip, and (c) a single incident photon of insufficient energy to create a normal-state belt but initiating a subsequent single-vortex crossing, which provides the rest of the energy needed to create the normal-state belt (vortex-assisted single-photon count). We derive the current dependence of the rate of vortex-assisted photon counts. The resulting photon count rate has a plateau at high currents close to the critical current and drops as a power law with high exponent at lower currents. While the magnetic field perpendicular to the film plane does not affect the formation of hot spots by photons, it causes the rate of vortex crossings (with or without photons) to increase. We show that by applying a magnetic field one may characterize the energy barrier for vortex crossings and identify the origin of dark counts and vortex-assisted photon counts.

arXiv:1108.4004•Physical Review B•Jan 17, 2012•130 citations

Characterization of MoSi superconducting single-photon detectors in magnetic field

Alexander A. Korneev, Yu. P. Korneeva, M. Yu. Mikhaı̆lov +9 more

We investigate the response mechanism of nanowire superconducting single-photon detectors (SSPDs) made of amorphous MoxSi1-x. We study the dependence of photon count and dark count rates on bias current in magnetic fields up to 113 mT at 1.7 K temperature. The observed behavior of photon counts is similar to the one recently observed in NbN SSPDs. Our results show that the detecting mechanism of relatively high-energy photons does not involve the vortex penetration from the edges of the film, and on the contrary, the detecting mechanism of low-energy photons probably involves the vortex penetration from the film edges.

IEEE Transactions on Applied Superconductivity•Jan 1, 2014•11 citations

Enhancement of critical currents and photon-count rates by magnetic field in spiral superconducting nanowire single-photon detectors

Ilya Charaev, Alexei D. Semenov, R. Lusche +3 more

We investigated the influence of magnetic fields on critical currents and photon count rates for optical and near-infrared photons in spiral-shaped nanowire structures of different types. Nanowires with a width of about 100 nm were made in forms of square and circular spirals with a pitch of 150 nm. Magnetic field dependencies of the critical current in square spirals were asymmetric with respect to the field direction. In the current maximum, we achieved a more than 6% increase of the critical current. On the contrary, circular spirals showed fully symmetric dependencies with the current maximum at zero magnetic field. Photon count rates of spirals have been studied in the wavelength range from 500 to 1400 nm at magnetic fields up to 500 mT. In circular spirals, the rates of photon and dark counts were symmetric in magnetic fields at all achievable experimental conditions. In square spirals, dark and photon count rates are asymmetric with the minima occurring at opposite directions of the field. Dark count rates are lower than 10 cps at bias currents up to 90% of the critical value in the whole range of applied magnetic fields. Based on our results, we propose a way to decrease the minimum detectable photon flux by applying external magnetic field to the detector.

IEEE Transactions on Applied Superconductivity•Jan 1, 2016•7 citations

Enhancement of photon detection in superconducting nanowire single photon detector exposed to oscillating magnetic field

Ilan Hakimi, Naor Vardi, Amos Sharoni +2 more

We measured the photon count rate (PCR) and dark count rate (DCR) of a superconducting nanowire single photon detector (SNSPD) exposed to either a DC magnetic field (up to 60 mT) or to a low-amplitude oscillating field (0.12–0.48 mT, up to 50 kHz). In both cases, the results show an increase in the PCR and the DCR as the DC field or the frequency of the AC field increase. However, the ratio DCR/(PCR + DCR) increases significantly with an increasing DC field, whereas this ratio is approximately constant as the frequency of the AC field increases up to frequencies in the kHz regime. The results suggest a more favorable effect of AC fields on the operation of the SNSPD.

Applied Physics Letters•Jun 7, 2021•3 citations

Different Single-Photon Response of Wide and Narrow Superconducting MoxSi1−x Strips

Yu. P. Korneeva, N.N. Manova, I.N. Florya +4 more

The photon count rate (PCR) of superconducting single-photon detectors made of ${\mathrm{Mo}}_{x}{\mathrm{Si}}_{1\text{\ensuremath{-}}x}$ films shaped as a 2-$\ensuremath{\mu}\mathrm{m}$-wide strip and a 115-nm-wide meander strip line is studied experimentally as a function of the dc biasing current at different values of the perpendicular magnetic field. For the wide strip, a crossover current ${I}_{\mathrm{cross}}$ is observed, below which the PCR increases with an increasing magnetic field and above which it decreases. This behavior contrasts with the narrow ${\mathrm{Mo}}_{x}{\mathrm{Si}}_{1\text{\ensuremath{-}}x}$ meander, for which no crossover current is observed, thus suggesting different photon-detection mechanisms in the wide and narrow strips. Namely, we argue that in the wide strip the absorbed photon destroys superconductivity locally via the vortex-antivortex mechanism for the emergence of resistance, while in the narrow meander superconductivity is destroyed across the whole strip line, forming a hot belt. Accordingly, the different photon-detection mechanisms associated with vortices and the hot belt determine the qualitative difference in the dependence of the PCR on the magnetic field.

arXiv:1910.02491•Physical Review Applied•Feb 6, 2020•59 citations
We have studied the influence of an externally applied magnetic field on the photon and dark count rates of meander-type niobium nitride superconducting nanowire single-photon detectors. Measurements have been performed at a temperature of 4.2 K, and magnetic fields up to 250 mT have been applied perpendicularly to the meander plane. While photon count rates are field independent at weak applied fields, they show a strong dependence at fields starting from approximately \ifmmode\pm\else\textpm\fi{}25 mT. This behavior, as well as the magnetic field dependence of the dark count rates, is in good agreement with the recent theoretical model of vortex-assisted photon detection and spontaneous vortex crossing in narrow superconducting lines. However, the local reduction of the superconducting free energy due to photon absorption, which is the fitting parameter in the model, increases much slower with the photon energy than the model predicts. Furthermore, changes in the free-energy during photon counts and dark counts depend differently on the current that flows through the meander. This indicates that photon counts and dark counts occur in different parts of the meander.
We have studied the magnetic-field dependence of both dark-count rates and photon-count rates in a superconducting nanowire single-photon detector made of TaN in external magnetic fields $|{\ensuremath{\mu}}_{0}H|<10$ mT perpendicular to the plane of the underlying meander structure and at T=4T=4T=4 K. The dark-count rates show a characteristic field dependence, which is asymmetric with respect to magnetic-field direction. The field and the current dependence of the dark counts can be quantitatively well explained if one assumes that the critical current is reduced to $\ensuremath{\approx}$5050%50 at the ${180}^{\ensuremath{\circ}}$ meander turns when compared to a straight strip, and the observed asymmetry can be modeled assuming that the turnarounds are not all strictly equal. Surprisingly, the photon-count rates do not show any significant field dependence, which seems to be at odds with existing detection models invoking vortex crossings.
We argue that photon counts in a superconducting nanowire single-photon detector (SNSPD) are caused by the transition from a current-biased metastable superconducting state to the normal state. Such a transition is triggered by vortices crossing the thin and narrow superconducting strip from one edge to another due to the Lorentz force. Detector counts in SNSPDs may be caused by three processes: (a) a single incident photon with sufficient energy to break enough Cooper pairs to create a normal-state belt across the entire width of the strip (direct photon count), (b) thermally induced single-vortex crossing in the absence of photons (dark count), which at high-bias currents releases the energy sufficient to trigger the transition to the normal state in a belt across the whole width of the strip, and (c) a single incident photon of insufficient energy to create a normal-state belt but initiating a subsequent single-vortex crossing, which provides the rest of the energy needed to create the normal-state belt (vortex-assisted single-photon count). We derive the current dependence of the rate of vortex-assisted photon counts. The resulting photon count rate has a plateau at high currents close to the critical current and drops as a power law with high exponent at lower currents. While the magnetic field perpendicular to the film plane does not affect the formation of hot spots by photons, it causes the rate of vortex crossings (with or without photons) to increase. We show that by applying a magnetic field one may characterize the energy barrier for vortex crossings and identify the origin of dark counts and vortex-assisted photon counts.
We investigate the response mechanism of nanowire superconducting single-photon detectors (SSPDs) made of amorphous MoxSi1-x. We study the dependence of photon count and dark count rates on bias current in magnetic fields up to 113 mT at 1.7 K temperature. The observed behavior of photon counts is similar to the one recently observed in NbN SSPDs. Our results show that the detecting mechanism of relatively high-energy photons does not involve the vortex penetration from the edges of the film, and on the contrary, the detecting mechanism of low-energy photons probably involves the vortex penetration from the film edges.
We investigated the influence of magnetic fields on critical currents and photon count rates for optical and near-infrared photons in spiral-shaped nanowire structures of different types. Nanowires with a width of about 100 nm were made in forms of square and circular spirals with a pitch of 150 nm. Magnetic field dependencies of the critical current in square spirals were asymmetric with respect to the field direction. In the current maximum, we achieved a more than 6% increase of the critical current. On the contrary, circular spirals showed fully symmetric dependencies with the current maximum at zero magnetic field. Photon count rates of spirals have been studied in the wavelength range from 500 to 1400 nm at magnetic fields up to 500 mT. In circular spirals, the rates of photon and dark counts were symmetric in magnetic fields at all achievable experimental conditions. In square spirals, dark and photon count rates are asymmetric with the minima occurring at opposite directions of the field. Dark count rates are lower than 10 cps at bias currents up to 90% of the critical value in the whole range of applied magnetic fields. Based on our results, we propose a way to decrease the minimum detectable photon flux by applying external magnetic field to the detector.
We measured the photon count rate (PCR) and dark count rate (DCR) of a superconducting nanowire single photon detector (SNSPD) exposed to either a DC magnetic field (up to 60 mT) or to a low-amplitude oscillating field (0.12–0.48 mT, up to 50 kHz). In both cases, the results show an increase in the PCR and the DCR as the DC field or the frequency of the AC field increase. However, the ratio DCR/(PCR + DCR) increases significantly with an increasing DC field, whereas this ratio is approximately constant as the frequency of the AC field increases up to frequencies in the kHz regime. The results suggest a more favorable effect of AC fields on the operation of the SNSPD.
The photon count rate (PCR) of superconducting single-photon detectors made of ${\mathrm{Mo}}_{x}{\mathrm{Si}}_{1\text{\ensuremath{-}}x}$ films shaped as a 2-$\ensuremath{\mu}\mathrm{m}$-wide strip and a 115-nm-wide meander strip line is studied experimentally as a function of the dc biasing current at different values of the perpendicular magnetic field. For the wide strip, a crossover current Icross{I}_{\mathrm{cross}}Icross​ is observed, below which the PCR increases with an increasing magnetic field and above which it decreases. This behavior contrasts with the narrow ${\mathrm{Mo}}_{x}{\mathrm{Si}}_{1\text{\ensuremath{-}}x}$ meander, for which no crossover current is observed, thus suggesting different photon-detection mechanisms in the wide and narrow strips. Namely, we argue that in the wide strip the absorbed photon destroys superconductivity locally via the vortex-antivortex mechanism for the emergence of resistance, while in the narrow meander superconductivity is destroyed across the whole strip line, forming a hot belt. Accordingly, the different photon-detection mechanisms associated with vortices and the hot belt determine the qualitative difference in the dependence of the PCR on the magnetic field.