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Tretyakov IV, Ryabchun SA, Maslennikov SN, Finkel MI, Kaurova NS, Seleznev VA, et al. NbN HEB mixer: fabrication, noise temperature reduction and characterization. In: Proc. Basic problems of superconductivity. Moscow-Zvenigorod; 2008.
Abstract: We demonstrate that in the terahertz region superconducting hot-electron mixers offer the lowest noise temperature, opening the possibility of using HTS's in the future to fabricate these devices. Specifically, a noise temperature of 950 K was measured for the receiver operating at 2.5 THz with a NbN HEB mixer, and a gain bandwidth of 6 GHz was measured at 300 GHz near Tc for the same mixer.
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Ryabchun SA, Tretyakov IV, Pentin IV, Kaurova NS, Seleznev VA, Voronov BM, et al. Low-noise wide-band hot-electron bolometer mixer based on an NbN film. Radiophys. Quant. Electron.. 2009;52(8):576–82.
Abstract: We develop and study a hot-electron bolometer mixer made of a two-layer NbN–Au film in situ deposited on a silicon substrate. The double-sideband noise temperature of the mixer is 750 K at a frequency of 2.5 THz. The conversion efficiency measurements show that at the superconducting transition temperature, the intermediate-frequency bandwidth amounts to about 6.5 GHz for a mixer 0.112 μm long. These record-breaking characteristics are attributed to the improved contacts between a sensitive element and a helical antenna and are reached due to using the in situ deposition of NbN and Au layers at certain stages of the process.
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Tret’yakov IV, Ryabchun SA, Kaurova NS, Larionov PA, Lobastova AA, Voronov BM, et al. Optimum absorbed heterodyne power for superconducting NbN hot-electron bolometer mixer. Tech Phys Lett. 2010;36(12):1103–5.
Abstract: Absorbed heterodyne power has been measured in a low-noise broadband hot-electron bolometer (HEB) mixer for the terahertz range, operating on the effect of electron heating in the resistive state of an ultrathin superconducting NbN film. It is established that the optimum absorbed heterodyne power for the HEB mixer operating at 2.5 THz is about 100 nW.
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Tuchak AN, Gol’tsman GN, Kitaeva GK, Penin AN, Seliverstov SV, Finkel MI, et al. Generation of nanosecond terahertz pulses by the optical rectification method. JETP Lett. 2012;96(2):94–7.
Abstract: The possibility of the generation of quasi-cw terahertz radiation by the optical rectification method for broad-band Fourier unlimited nanosecond laser pulses has been experimentally demonstrated. The broadband radiation of a LiF dye-center laser is used as a pump source of a nonlinear optical oscillator. The energy efficiency of terahertz optical frequency conversion in a periodically polarized lithium niobate crystal is 4 × 10−9 at a pump power density of 7 MW/cm2.
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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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