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Smirnov K, Korneev A, Minaeva O, Divochiy A, Tarkhov M, Ryabchun S, et al. Ultrathin NbN film superconducting single-photon detector array. In: J. Phys.: Conf. Ser. Vol 61.; 2007. p. 1081–5.
Abstract: We report on the fabrication process of the 2 × 2 superconducting single-photon detector (SSPD) array. The SSPD array is made from ultrathin NbN film and is operated at liquid helium temperatures. Each detector is a nanowire-based structure patterned by electron beam lithography process. The advances in fabrication technology allowed us to produce highly uniform strips and preserve superconducting properties of the unpatterned film. SSPD exhibit up to 30% quantum efficiency in near infrared and up to 1% at 5-μm wavelength. Due to 120 MHz counting rate and 18 ps jitter, the time-domain multiplexing read-out is proposed for large scale SSPD arrays. Single-pixel SSPD has already found a practical application in non-invasive testing of semiconductor very-large scale integrated circuits. The SSPD significantly outperformed traditional single-photon counting avalanche diodes.
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Seleznev VA, Divochiy AV, Vakhtomin YB, Morozov PV, Zolotov PI, Vasil'ev DD, et al. Superconducting detector of IR single-photons based on thin WSi films. In: J. Phys.: Conf. Ser. Vol 737.; 2016. 012032.
Abstract: We have developed the deposition technology of WSi thin films 4 to 9 nm thick with high temperature values of superconducting transition (Tc~4 K). Based on deposed films there were produced nanostructures with indicative planar sizes ~100 nm, and the research revealed that even on nanoscale the films possess of high critical temperature values of the superconducting transition (Tc~3.3-3.7 K) which certifies high quality and homogeneity of the films created. The first experiments on creating superconducting single-photon detectors showed that the detectors' SDE (system detection efficiency) with increasing bias current (I b) reaches a constant value of ~30% (for X=1.55 micron) defined by infrared radiation absorption by the superconducting structure. To enhance radiation absorption by the superconductor there were created detectors with cavity structures which demonstrated a practically constant value of quantum efficiency >65% for bias currents Ib>0.6-Ic. The minimal dark counts level (DC) made 1 s-1 limited with background noise. Hence WSi is the most promising material for creating single-photon detectors with record SDE/DC ratio and noise equivalent power (NEP).
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Smirnov E, Golikov A, Zolotov P, Kovalyuk V, Lobino M, Voronov B, et al. Superconducting nanowire single-photon detector on lithium niobate. In: J. Phys.: Conf. Ser. Vol 1124.; 2018. 051025.
Abstract: We demonstrate superconducting niobium nitride nanowires folded on top of lithium niobate substrate. We report of 6% system detection efficiency at 20 s−1 dark count rate at telecommunication wavelength (1550 nm). Our results shown great potential for the use of NbN nanowires in the field of linear and nonlinear integrated quantum photonics.
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Moshkova M, Morozov P, Divochiy A, Vakhtomin Y, Smirnov K. Large active area superconducting single photon detector. In: J. Phys.: Conf. Ser. Vol 1410.; 2019. 012139.
Abstract: We present development of large active area superconducting single-photon detectors well coupled with standard 50 μm-core multi-mode fiber. The sensitive area of the SSPD is patterned using the photon-number-resolving design and occupies an area of 40×40 μm2. Using this approach, we have obtained excellent specifications: system detection efficiency of 47% measured using a 900 nm laser and low dark count rate of 100 cps. The main advantages of the approach presented are a very short dead time of the detector of 22 ns and FWHM jitter value of about 130 ps.
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Zolotov PI, Divochiy AV, Vakhtomin YB, Lubenchenko AV, Morozov PV, Shurkaeva IV, et al. Influence of sputtering parameters on the main characteristics of ultra-thin vanadium nitride films. In: J. Phys.: Conf. Ser. Vol 1124.; 2018. 051030.
Abstract: We researched the relation between deposition and ultra-thin VN films parameters. To conduct the experimental study we varied substrate temperature, Ar and N2 partial pressures and deposition rate. The study allowed us to obtain the films with close to the bulk values transition temperatures and implement such samples in order to fabricate superconducting single-photon detectors.
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