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Jiang L, Antipov SV, Voronov BM, Gol'tsman GN, Zhang W, Li N, et al. Characterization of the performance of a quasi-optical NbN superconducting HEB mixer. IEEE Trans Appl Supercond. 2007;17(2):395–8.
Abstract: In this paper we focus mainly on the investigation of the performance of a quasi-optical (planar log-spiral antenna) phonon-cooled NbN superconducting hot electron bolometer (HEB) mixer, which is cryogenically cooled by a close-cycled 4-K cryocooler, at 500 and 850 GHz frequency bands. The mixer's noise performance, stability of IF output power, and local oscillator (LO) power requirement are characterized for three NbN superconducting HEB devices of different sizes. The transmission characteristics of Mylar and Zitex films with incidence waves of an elliptical polarization are also examined by measuring the mixer's noise temperature. The lowest receiver noise temperatures (with no corrections) of 750 and 1100 K are measured at 500 and 850 GHz, respectively. Experimental results also demonstrate that the bigger the HEB device is, the higher the stability of IF output power becomes.
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Jiang L, Miao W, Zhang W, Li N, Lin ZH, Yao QJ, et al. Characterization of a quasi-optical NbN superconducting HEB mixer. IEEE Trans Microwave Theory Techn. 2006;54(7):2944–8.
Abstract: In this paper, the performance of a quasi-optical NbN superconducting hot-electron bolometer (HEB) mixer, cryogenically cooled by a close-cycled 4-K refrigerator, is thoroughly investigated at 300, 500, and 850 GHz. The lowest receiver noise temperatures measured at the respective three frequencies are 1400, 900, and 1350 K, which can go down to 659, 413, and 529 K, respectively, after correcting the loss and associated noise contribution of the quasi-optical system before the measured superconducting HEB mixer. The stability of the quasi-optical superconducting HEB mixer is also investigated here. The Allan variance time measured with a local oscillator pumping at 500 GHz and an IF bandwidth of 110 MHz is 1.5 s at the dc-bias voltage exhibiting the lowest noise temperature and increases to 2.5 s at a dc bias twice that voltage.
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Antipov SV, Svechnikov SI, Smirnov KV, Vakhtomin YB, Finkel MI, Goltsman GN, et al. Noise temperature of quasioptical NbN hot electron bolometer mixers at 900 GHz. Physics of Vibrations. 2001;9(4):242–5.
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Svechnikov SI, Antipov SV, Vakhtomin YB, Goltsman GN, Gershenzon EM, Cherednichenko SI, et al. Conversion and noise bandwidths of terahertz NbN hot-electron bolometer mixers. Physics of Vibrations. 2001;9(3):205–10.
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Smirnov KV, Ptitsina NG, Vakhtomin YB, Verevkin AA, Gol’tsman GN, Gershenzon EM. Energy relaxation of two-dimensional electrons in the quantum Hall effect regime. JETP Lett. 2000;71(1):31–4.
Abstract: The mm-wave spectroscopy with high temporal resolution is used to measure the energy relaxation times τe of 2D electrons in GaAs/AlGaAs heterostructures in magnetic fields B=0–4 T under quasi-equilibrium conditions at T=4.2 K. With increasing B, a considerable increase in τe from 0.9 to 25 ns is observed. For high B and low values of the filling factor ν, the energy relaxation rate τ −1e oscillates. The depth of these oscillations and the positions of maxima depend on the filling factor ν. For ν>5, the relaxation rate τ −1e is maximum when the Fermi level lies in the region of the localized states between the Landau levels. For lower values of ν, the relaxation rate is maximum at half-integer values of τ −1e when the Fermi level is coincident with the Landau level. The characteristic features of the dependence τ −1e (B) are explained by different contributions of the intralevel and interlevel electron-phonon transitions to the process of the energy relaxation of 2D electrons.
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Moshkova MA, Morozov PV, Antipov AV, Vakhtomin YB, Smirnov KV. High-efficiency multi-element superconducting single-photon detector. In: Prochazka I, Štefaňák M, Sobolewski R, Gábris A, editors. Proc. SPIE. Vol 11771. SPIE; 2021. p. 2–8.
Abstract: We present the result of the creation and investigation of the multi-element superconducting single photon detectors, which can recognize the number of photons (up to six) in a short pulse of the radiation at telecommunication wavelengths range. The best receivers coupled with single-mode fiber have the system quantum efficiency of ⁓85%. The receivers have a 100 ps time resolution and a few nanoseconds dead time that allows them to operate at megahertz counting rate. Implementation of the multi-element architecture for creation of the superconducting single photon detectors with increased sensitive area allows to create the high efficiency receivers coupled with multi-mode fibers and with preserving of the all advantages of superconducting photon counters.
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Vasilev DD, Malevannaya EI, Moiseev KM, Zolotov PI, Antipov AV, Vakhtomin YB, et al. Influence of deposited material energy on superconducting properties of the WSi films. In: IOP Conf. Ser.: Mater. Sci. Eng. Vol 781.; 2020. 012013 (1 to 6).
Abstract: WSi thin films have the advantages for creating SNSPDs with a large active area or array of detectors on a single substrate due to the amorphous structure. The superconducting properties of ultrathin WSi films substantially depends on their structure and thickness as the NbN films. Scientific groups investigating WSi films mainly focused only on changes of their thickness and the ratio of the components on the substrate at room temperature. This paper presents experiments to determine the effect of the bias potential on the substrate, the temperature of the substrate, and the peak power of pulsed magnetron sputtering, which is the equivalent of ionization, a tungsten target, on the surface resistance and superconducting properties of the WSi ultrathin films. The negative effect of the substrate temperature and the positive effect of the bias potential and the ionization coefficient (peak current) allow one to choose the best WSi films formation mode for SNSPD: substrate temperature 297 K, bias potential -60 V, and peak current 3.5 A.
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Antipov AV, Seleznev VA, Vakhtomin YB, Morozov PV, Vasilev DD, Malevannaya EI, et al. Investigation of WSi and NbN superconducting single-photon detectors in mid-IR range. In: IOP Conf. Ser.: Mater. Sci. Eng. Vol 781.; 2020. 012011 (1 to 5).
Abstract: Spectral characteristics of WSi and NbN superconducting single-photon detectors with different surface resistance and width of nanowire strips have been investigated in the wavelength range of 1.3-2.5 μm. WSi structures with narrower strips demonstrated better performance for detection of single photons in longer wavelength range. The difference in normalized photon count rate for such structures reaches one order of magnitude higher in comparison with structures based on NbN thin films at 2.5 μm.
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Kitaeva GK, Kornienko VV, Kuznetsov KA, Pentin IV, Smirnov KV, Vakhtomin YB. Direct detection of the idler THz radiation generated by spontaneous parametric down-conversion. Opt Lett. 2019;44(5):1198–201.
Abstract: We study parametric down-conversion (PDC) of optical laser radiation in the strongly frequency non-degenerate regime which is promising for the generation of quantum-correlated pairs of extremely different spectral ranges, the optical and the terahertz (THz) ones. The possibility to detect tenuous THz-frequency photon fluxes generated under low-gain spontaneous PDC is demonstrated using a hot electron bolometer. Then experimental dependences of the THz radiation power on the detection angle and on the pump intensity are analyzed.
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Kuznetsov KA, Kornienko VV, Vakhtomin YB, Pentin IV, Smirnov KV, Kitaeva GK. Generation and detection of optical-terahertz biphotons via spontaneous parametric downconversion. In: Proc. ICLO.; 2018. 303.
Abstract: We study spontaneous parametric downconversion (SPDC) in the strongly non-degenerate regime when the idler wave hits the terahertz range. By using the hot-electron bolometer, for the first time the SPDC-generated idler-wave photons were directly detected in the terahertz frequency range. Spectrum of corresponding signal photons was measured using standard technique by the CCD camera. Possible applications of correlated optical-terahertz biphotons are discussed.
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