Reduced dark counts in optimized geometries for superconducting nanowire single photon detectors

Akhlaghi, Mohsen K.; Atikian, Haig A.; Eftekharian, Amin; Lončar, Marko; Majedi, A. Hamed

doi:10.1364/oe.20.023610

Cited by 44 publications

(37 citation statements)

References 14 publications

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“…The strength of the suppression is dependent on the particular geometry of the superconducting structure as well as on the angle and the radius r of the bend and the ratio of the coherence length to the width of the strip ξ GL /w. Several experiments by different groups [29][30][31] have confirmed the predictions of [28]. It has been shown that the current crowding is stronger for wider superconducting strips but becomes weaker with an increase of the radius of the bend.…”

Section: Stationary State Of Snspdmentioning

confidence: 59%

“…It is most plausibly explained in meanders by different origins for these events. Current assisted photon counts come mostly from straight segments of the meander while fluctuation assisted photon and dark counts originate from bends [29,61,67]. This does not exclude the possibility that dark counts in the straight fragments of meanders or in nanobridges Detection mechanism of SNSPDs 20 have a different mechanism as compared to photon counts [102].…”

Section: Magnetic-field Dependence Of Photon Countsmentioning

confidence: 98%

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Detection mechanism of superconducting nanowire single-photon detectors

Engel¹,

Renema²,

Ilin³

et al. 2015

Supercond. Sci. Technol.

149

111

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Abstract. In this paper we intend to give a comprehensive description of the current understanding of the detection mechanism in superconducting nanowire singlephoton detectors. We will review key experimental results related to the detection mechanism, e.g. the variations of the detection probability as a function of bias current, temperature or magnetic field. Commonly used detection models will be introduced and we will analyze their predictions in view of the experimental observations. Although none of the proposed detection models is able to describe all experimental data, it is becoming increasingly clear that vortices are essential for the formation of the initial normal-conducting domain that triggers a detection event.

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Section: Stationary State Of Snspdmentioning

confidence: 59%

Section: Magnetic-field Dependence Of Photon Countsmentioning

confidence: 98%

Detection mechanism of superconducting nanowire single-photon detectors

Engel¹,

Renema²,

Ilin³

et al. 2015

Supercond. Sci. Technol.

149

111

View full text Add to dashboard Cite

show abstract

“…Due to a current-crowding effect the current density in the 180 turnarounds of the meander structure is no longer homogeneous 27 and dark-count events most likely originate near these turnarounds, 28 but may be reduced by a more sophisticated meander design. 29 Despite this remarkable progress in understanding and optimization of SNSPD, some open questions remain, particularly in connection with the mechanism that is responsible for triggering the initial resistive cross-section. The first model 30 describing the detection mechanism in SNSPD assumed the formation of a normal-conducting hot-spot that diverts the applied bias current into the still superconducting side-walks.…”

Section: Introductionmentioning

confidence: 99%

Numerical analysis of detection-mechanism models of superconducting nanowire single-photon detector

Engel

Schilling

2013

Journal of Applied Physics

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The microscopic mechanism of photon detection in superconducting nanowire single-photon detectors is still under debate. We present a simple but powerful theoretical model that allows us to identify essential differences between competing detection mechanisms. The model is based on quasi-particle multiplication and diffusion after the absorption of a photon. We then use the calculated spatial and temporal evolution of this quasi-particle cloud to determine detection criteria of three distinct detection mechanisms, based on the formation of a normal conducting spot, the reduction of the effective depairing critical current below the bias current, and a vortex-crossing scenario, respectively. All our calculations as well as a comparison to experimental data strongly support the vortex-crossing detection mechanism by which vortices and antivortices enter the superconducting strip from the edges and subsequently traverse it thereby triggering the detectable normal conducting domain. These results may therefore help to reveal the microscopic mechanism responsible for the detection of photons in superconducting nanowires. V C 2013 AIP Publishing LLC.

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“…This could enable transmission of quantum information and distribution of quantum entanglement [9, 10] over long distances, for the realization of quantum repeaters. Such an integrated diamond quantum photonics platform would benefit from the realization of high performance single photon detectors, with broadband photon sensitivity, that are integrated directly on the same diamond chip.Superconducting nanowire single photon detectors (SNSPDs) outperform other single photon detector technologies on several merits such as quantum efficiency [11], timing jitter, dark count rates, and broad spectral sensitivity [12,13]. SNSPDs typically consist of narrow width nanowires patterned into an ultrathin (4nm to 8nm) superconducting film, commonly made from niobium nitride or some derivative of [14].…”

mentioning

confidence: 99%

Superconducting nanowire single photon detector on diamond

Atikian

Eftekharian

Salim

et al. 2014

Applied Physics Letters

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Superconducting nanowire single photon detectors (SNSPDs) are fabricated directly on diamond substrates and their optical and electrical properties are characterized. Dark count performance and photon count rates are measured at varying temperatures for 1310nm and 632nm photons. The procedure to prepare diamond substrate surfaces suitable for the deposition and patterning of thin film superconducting layers is reported. Using this approach, diamond substrates with less than 300pm RMS surface roughness are obtained.Diamond has recently gained significant interest as a promising platform for on-chip high-performance photonic devices [1][2][3]. Diamond exhibits many favorable material properties such as a high refractive index (n=2.4), wide bandgap (5.5eV), and a large optical transmission range from the UV to the mid infrared. Diamond is also host to numerous defect color centers such as the nitrogen-vancancy (NV) center, that can be utilized as an optically addressable spin based memory, particularly interesting in the field of quantum information processing [4,5]. In addition, diamond has a relatively large Kerr non-linearity [6] (n 2 = 1.3 · 10 −19 m 2 /W) making it an attractive platform for on-chip nonlinear optics in the visible and infrared wavelengths [7]. An exciting application for utilizing this diamond non-linearity could allow for frequency conversion of photons generated by color centers in diamond, which typically emit in the visible range, to the telecom wavelengths [8]. This could enable transmission of quantum information and distribution of quantum entanglement [9, 10] over long distances, for the realization of quantum repeaters. Such an integrated diamond quantum photonics platform would benefit from the realization of high performance single photon detectors, with broadband photon sensitivity, that are integrated directly on the same diamond chip.Superconducting nanowire single photon detectors (SNSPDs) outperform other single photon detector technologies on several merits such as quantum efficiency [11], timing jitter, dark count rates, and broad spectral sensitivity [12,13]. SNSPDs typically consist of narrow width nanowires patterned into an ultrathin (4nm to 8nm) superconducting film, commonly made from niobium nitride or some derivative of [14]. The nanowires are current biased close to the critical current of the superconductor. When an incident photon is absorbed by the wire, a small resistive hotspot is formed generating a voltage pulse that can be subsequently amplified and measured [15]. Since the performance of SNSPDs is critically * loncar@seas.harvard.edu dependent on nanowire structural uniformity, it is crucial to have them deposited on smooth substrate surfaces to avoid constrictions that can have detrimental effects on detection efficiency [16].In this letter, we report NbTiN superconducting nanowires deposited directly on diamond substrates that exhibit promising single photon sensitivity. Specifically, we provide details of the fabrication procedure developed, resulting in ...

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Reduced dark counts in optimized geometries for superconducting nanowire single photon detectors

Cited by 44 publications

References 14 publications

Detection mechanism of superconducting nanowire single-photon detectors

Detection mechanism of superconducting nanowire single-photon detectors

Numerical analysis of detection-mechanism models of superconducting nanowire single-photon detector

Superconducting nanowire single photon detector on diamond

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