Cherednichenko S, Kroug M, Merkel H, Kollberg E, Loudkov D, Smirnov K, et al. Local oscillator power requirement and saturation effects in NbN HEB mixers. In: Jet Propulsion Laboratory CIit.u.t.e of T, editor. Proc. 12th Int. Symp. Space Terahertz Technol. San Diego, CA, USA; 2001. p. 273–85.
Abstract: The local oscillator power required for NbN hot-electron bolometric mixers (P LO ) was investigated with respect to mixer size, critical temperature and ambient temperature. P LO can be decreased by a factor of 10 as the mixer size decreases from 4×0.4 µm 2 to 0.6×0.13 µm 2 . For the smallest volume mixer the optimal local oscillator power was found to be 15 nW. We found that for such mixer no signal compression was observed up to an input signal of 2 nW which corresponds to an equivalent input load of 20,000 K. For a constant mixer volume, reduction of T c can decrease optimal local oscillator power at least by a factor of 2 without a deterioration of the receiver noise temperature. Bath temperature was found to have minor effect on the receiver characteristics.
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Kroug M, Cherednichenko S, Choumas M, Merkel H, Kollberg E, Hübers H-W, et al. HEB quasi-optical heterodyne receiver for THz frequencies. In: Proc. 12th Int. Symp. Space Terahertz Technol. San Diego, CA, USA; 2001. p. 244–52.
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Maslennikov S, Antipov S, Shishkov A, Svechnikov S, Voronov B, Smirnov K, et al. NbN HEB mixer noise temperature measurements with hot/cold load mounted inside the helium cryostat at 300 GHz. In: Proc. Int. Student Seminar on Microwave Appl. of Novel Physical Phenomena supported by IEEE. St.-Petersburg: LETI; 2002.
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Hübers H-W, Semenov AD, Richter H, Schubert J, Hadjiloucas S, Bowen JW, et al. Antenna pattern of the quasi-optical hot-electron bolometric mixer at terahertz frequencies. In: Proc. 12th Int. Symp. Space Terahertz Technol. San Diego, CA, USA; 2001. p. 286–96.
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Ferrari S, Kovalyuk V, Hartmann W, Vetter A, Kahl O, Lee C, et al. Hot-spot relaxation time current dependence in niobium nitride waveguide-integrated superconducting nanowire single-photon detectors. Opt Express. 2017;25(8):8739–50.
Abstract: We investigate how the bias current affects the hot-spot relaxation dynamics in niobium nitride. We use for this purpose a near-infrared pump-probe technique on a waveguide-integrated superconducting nanowire single-photon detector driven in the two-photon regime. We observe a strong increase in the picosecond relaxation time for higher bias currents. A minimum relaxation time of (22 +/- 1)ps is obtained when applying a bias current of 50% of the switching current at 1.7 K bath temperature. We also propose a practical approach to accurately estimate the photon detection regimes based on the reconstruction of the measured detector tomography at different bias currents and for different illumination conditions.
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