Detection mechanism of superconducting nanowire single-photon detectors

Engel, A.; Renema, Jelmer J.; Ilin, K.; Semenov, A.

doi:10.1088/0953-2048/28/11/114003

Cited by 149 publications

(117 citation statements)

References 123 publications

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“…While our results add additional data, the question of the detection mechanism remains an open problem. Interestingly, some recent theoretical works are predicting nonlinear energy-current relations, 23,28,32,34 but a direct comparison between these theories and our results will require more work.…”

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confidence: 71%

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Optically probing the detection mechanism in a molybdenum silicide superconducting nanowire single-photon detector

Caloz

Korzh

Timoney

et al. 2017

Applied Physics Letters

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We experimentally investigate the detection mechanism in a meandered molybdenum silicide (MoSi) superconducting nanowire single-photon detector by characterising the detection probability as a function of bias current in the wavelength range of 750 to 2050 nm. Contrary to some previous observations on niobium nitride (NbN) or tungsten silicide (WSi) detectors, we find that the energycurrent relation is nonlinear in this range. Furthermore, thanks to the presence of a saturated detection efficiency over the whole range of wavelengths, we precisely quantify the shape of the curves. This allows a detailed study of their features, which are indicative of both Fano fluctuations and position-dependent effects.

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confidence: 71%

“…22 Despite the extensive studies, the question remains if these differences are due to a fundamentally different detection mechanism. 23 Moreover, understanding the nature of the detection mechanism may ultimately lead to novel SNSPD structures with better performances or SNSPD-inspired devices targeting a broader range of applications.…”

mentioning

confidence: 99%

Optically probing the detection mechanism in a molybdenum silicide superconducting nanowire single-photon detector

Caloz

Korzh

Timoney

et al. 2017

Applied Physics Letters

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“…Additionally, the time constants of the W x Si 1−x films that are relevant for photon detection were acquired by means of measurements of the magnetoconductivity and time-resolving recovery after femtosecond optical excitation. We used our diffusion-based vortex-entry model [27][28][29] for analyzing the detection mechanism and defining the size of the hotspot (namely, the diameter of the hotspot), which is produced in our films by single photon excitation.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of superconducting tungsten silicide WxSi1−x for single photon detection

et al. 2016

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Superconducting properties of three series of amorphous W x Si 1x films with different thickness and stoichiometry were investigated by dc transport measurements in a magnetic field up to 9 T. These amorphous W x Si 1x films were deposited by magnetron cosputtering of the elemental source targets onto silicon substrates at room temperature and patterned in the form of bridges by optical lithography and reactive ion etching. Analysis of the data on magnetoconductivity allowed us to extract the critical temperatures, superconducting coherence lengths, magnetic penetration depths, and diffusion constants of electrons in the normal state as functions of film thickness for each stoichiometry. Two basic time constants were derived from transport and time-resolving measurements. A dynamic process of the formation of a hotspot was analyzed in the framework of a diffusion-based vortex-entry model. We used a two-stage diffusion approach and defined a hotspot size by assuming that the quasiparticles and normal-state electrons have the same diffusion constant. With this definition and these measured material parameters, the hotspot in the 5-nm-thick W 0.85 Si 0.15 film had a diameter of 107 nm at the peak of the number of nonequilibrium quasiparticles. Superconducting properties of three series of amorphous W x Si 1−x films with different thickness and stoichiometry were investigated by dc transport measurements in a magnetic field up to 9 T. These amorphous W x Si 1−x films were deposited by magnetron cosputtering of the elemental source targets onto silicon substrates at room temperature and patterned in the form of bridges by optical lithography and reactive ion etching. Analysis of the data on magnetoconductivity allowed us to extract the critical temperatures, superconducting coherence lengths, magnetic penetration depths, and diffusion constants of electrons in the normal state as functions of film thickness for each stoichiometry. Two basic time constants were derived from transport and time-resolving measurements. A dynamic process of the formation of a hotspot was analyzed in the framework of a diffusion-based vortex-entry model. We used a two-stage diffusion approach and defined a hotspot size by assuming that the quasiparticles and normal-state electrons have the same diffusion constant. With this definition and these measured material parameters, the hotspot in the 5-nm-thick W 0.85 Si 0.15 film had a diameter of 107 nm at the peak of the number of nonequilibrium quasiparticles.

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“…Our recent experimental results [20] as well as the improved understanding of the detection mechanism in SSPDs [21][22][23] show that the edges of an SSPD are generally more efficient than the center of the wire. Hence, the internal detection efficiency (IDE) depends on position , photon energy and bias current and is described by a quantity that we call the local detection efficiency arXiv:1612.02840v2 [physics.ins-det] 14 Jun 2017 LDE(x, I b ).…”

Section: Introductionmentioning

confidence: 84%

Design of NbN superconducting nanowire single photon detectors with enhanced infrared photon detection efficiency

Wang

Renema

Engel

et al. 2017

Quantum Information and Measurement (QIM) 2017

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We optimize the design of NbN nanowire superconducting single photon detectors, using the recently discovered position dependent detection efficiency in these devices. This optimized design of meandering wire NbN detectors maximizes absorption at positions where photon detection is most efficient by altering the field distribution across the wire. In order to calculate the response of the detectors with different geometries, we use a monotonic local detection efficiency from a nanowire and optical absorption distribution via finite-different-time-domain simulations. The calculations predict a trade-off between average absorption and absorption at the edge, leading to a predicted optimal wire width close to 100 nm for 1550 nm wavelength, which drops to 50 nm wire width for 600 nm wavelength. The absorption at the edges can be enhanced by depositing a silicon nanowire on top of the superconducting nanowire, which improves both the total absorption efficiency as well as the internal detection efficiency of meandering wire structures. The proposed structure can be integrated in a relatively simple cavity structure to reach absorption efficiencies of 97% for perpendicular and 85% for parallel polarization.

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Detection mechanism of superconducting nanowire single-photon detectors

Cited by 149 publications

References 123 publications

Optically probing the detection mechanism in a molybdenum silicide superconducting nanowire single-photon detector

Optically probing the detection mechanism in a molybdenum silicide superconducting nanowire single-photon detector

Characteristics of superconducting tungsten silicide WxSi1−x for single photon detection

Design of NbN superconducting nanowire single photon detectors with enhanced infrared photon detection efficiency

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