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Lobanov YV, Tong C-YE, Hedden AS, Blundell R, Gol'tsman GN. Microwave-assisted슠measurement슠of the슠frequency슠response슠of슠terahertz슠HEB슠mixers슠with a슠fourier슠transform슠spectrometer. In: 21st International Symposium on Space Terahertz Technology.; 2010. p. 420–3.
Abstract: We describe a novel method of operation of the HEB direct detector for use with a Fourier Transform Spectrometer. Instead of elevating the bath temperature, we have measured the RF response of waveguide HEB mixers by applying microwave radiation to select appropriate bias conditions. In our experiment, a microwave signal is injected into the HEB mixer via its IF port. By choosing an appropriate injection level, the device can be operated close to the desired operating point. Furthermore, we have shown that both thermal biasing and microwave injection can reproduce the same spectral response of the HEB mixer. However, with the use of microwave injection, there is no need to wait for the mixer to reach thermal equilibrium, so characterisation can be done in less time. Also, the liquid helium consumption for our wet cryostat is also reduced. We have demonstrated that the signalto-noise ratio of the FTS measurements can be improved with microwave injection.
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Chuprina IN, An PP, Zubkova EG, Kovalyuk VV, Kalachev AA, Gol'tsman GN. Optimisation of spontaneous four-wave mixing in a ring microcavity. In: J. Phys.: Conf. Ser. Vol 47.; 2017. p. 887–91.
Abstract: Abstract. A theory of spontaneous four-wave mixing in a ring microcavity is developed. The rate of emission of biphotons for pulsed and monochromatic pumping with allowance for the disper- sion of group velocities is analytically calculated. In the first case, pulses in the form of an increasing exponential are considered, which are optimal for excitation of an individual resonator mode. The behaviour of the group velocity dispersion as a function of the width and height of the waveguide is studied for a specific case of a ring microcavity made of silicon nitride. The results of the numeri- cal calculation are in good agreement with the experimental data. The ring microcavity is made of two types of waveguides: com- pletely etched and half etched. It is found that the latter allow for better control over the parameters in the manufacturing process, making them more predictable.
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Gershenzon EM, Gershenzon ME, Gol'tsman GN, Semenov AD, Sergeev AV. Heating of electrons in a superconductor in the resistive state by electromagnetic radiation. Sov Phys JETP. 1984;59(2):442–50.
Abstract: The effect of heating of electrons relative to phonons is observed and investigated in a superconducting film that is made resistive by current and by an external magnetic field. The effect is manifested by an increase of the film resistance under the influence of the electromagnetic radiation, and is not selective in the frequency band 10^10-10^15 Hz. The independence of the effect of frequency under conditions of strong scattering by static defects is attributed to the decisive role of electron-electron collisions in the distribution function. The experimentally obtained characteristic time of resistance variation near the superconducting transition corresponds to the relaxation time of the order parameter, while at lower temperatures and fields it corresponds to the time of the inelastic electron-phonon interaction.
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Vachtomin YB, Antipov SV, Kaurova NS, Maslennikov SN, Smirnov KV, Polyakov SL, et al. Noise temperature, gain bandwidth and local oscillator power of NbN phonon-cooled HEB mixer at terahertz frequenciess. In: Proc. 29th IRMMW / 12th THz. Karlsruhe, Germany; 2004. p. 329–30.
Abstract: We present the performances of HEB mixers based on 3.5 nm thick NbN film integrated with log-periodic spiral antenna. The double side-band receiver noise temperature values are 1300 K and 3100 K at 2.5 THz and at 3.8 THz, respectively. The gain bandwidth of the mixer is 4.2 GHz and the noise bandwidth is 5 GHz. The local oscillator power is 1-3 /spl mu/W for mixers with different active area.
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Smirnov KV, Vakhtomin YB, Divochiy AV, Ozhegov RV, Pentin IV, Gol'tsman GN. Infrared and terahertz detectors on basis of superconducting nanostructures. In: IEEE, editor. Microwave and Telecom. Technol. (CriMiCo), 20th Int. Crimean Conf.; 2010. p. 823–4.
Abstract: Results of development of single-photon receiving systems of visible, infrared and terahertz range based on thin-film superconducting nanostructures are presented. The receiving systems are produced on the basis of superconducting nanostructures, which function by means of hot-electron phenomena.
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