Korneeva YP, Manova NN, Dryazgov MA, Simonov NO, Zolotov PI, Korneev AA. Influence of sheet resistance and strip width on the detection efficiency saturation in micron-wide superconducting strips and large-area meanders. Supercond Sci Technol. 2021;34(8):084001.
Abstract: We report our study of detection efficiency (DE) saturation in wavelength range 400 – 1550 nm for the NbN Superconducting Microstrip Single-Photon Detectors (SMSPD) featuring the strip width up to 3 μm. We observe an expected decrease of the $DE$ saturation plateau with the increase of photon wavelength and decrease of film sheet resistance. At 1.7 K temperature DE saturation can be clearly observed at 1550 nm wavelength in strip with the width up to 2 μm when sheet resistance of the film is above 630Ω/sq. In such strips the length of the saturation plateau almost does not depend on the strip width. We used these films to make meander-shaped detectors with the light sensitive area from 20×20μm2 to a circle 50 μm in diameter. In the latter case, the detector with the strip width of 0.49 μm demonstrates saturation of DE up to 1064 nm wavelength. Although DE at 1310 and 1550 nm is not saturated, it is as high as 60%. The response time is limited by the kinetic inductance and equals to 20 ns(by 1/e decay), timing jitter is 44 ps. When coupled to multi-mode fibre large-area meanders demonstrate significantly higher dark count rate which we attribute to thermal background photons, thus advanced filtering technique would be required for practical applications.
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Korneev AA, Korneeva YP, Mikhailov MY, Pershin YP, Semenov AV, Vodolazov DY, et al. Characterization of MoSi superconducting single-photon detectors in the magnetic field. IEEE Trans Appl Supercond. 2015;25(3):2200504 (1 to 4).
Abstract: 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.
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Goltsman GN, Korneev AA, Finkel MI, Divochiy AV, Florya IN, Korneeva YP, et al. Superconducting hot-electron bolometer as THz mixer, direct detector and IR single-photon counter [abstract]. In: 35th Int. Conf. Infrared, Millimeter, and Terahertz Waves.; 2010. p. 1.
Abstract: We present a new generation of superconducting single-photon detectors (SSPDs) and hot-electron superconducting sensors with record characteristic for many terahertz and optical applications.
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Korneeva YP, Mikhailov MY, Pershin YP, Manova NN, Divochiy AV, Vakhtomin YB, et al. Superconducting single-photon detector made of MoSi film. Supercond Sci Technol. 2014;27(9):095012.
Abstract: We fabricated and characterized nanowire superconducting single-photon detectors made of 4 nm thick amorphous Mox Si1−x films. At 1.7 K the best devices exhibit a detection efficiency (DE) up to 18% at 1.2 $\mu {\rm m}$ wavelength of unpolarized light, a characteristic response time of about 6 ns and timing jitter of 120 ps. The DE was studied in wavelength range from 650 nm to 2500 nm. At wavelengths below 1200 nm these detectors reach their maximum DE limited by photon absorption in the thin MoSi film.
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Florya IN, Korneeva YP, Sidorova MV, Golikov AD, Gaiduchenko IA, Fedorov GE, et al. Energy relaxtation and hot spot formation in superconducting single photon detectors SSPDs. In: EPJ Web of Conferences. Vol 103.; 2015. 10004 (1 to 2).
Abstract: We have studied the mechanism of energy relaxation and resistive state formation after absorption of a single photon for different wavelengths and materials of single photon detectors. Our results are in good agreement with the hot spot model.
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