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Author Гольцман, Г.Н.; Лудков, Д.Н.
Title Сверхпроводниковые смесители на горячих электронах терагерцового диапазона и их применение в радиоастрономии Type Journal Article
Year 2003 Publication Изв. высших учебных заведений. Радиофизика Abbreviated Journal
Volume 46 Issue 8/9 Pages
Keywords (up) HEB, mixers
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Language russian Summary Language Original Title
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Notes Approved no
Call Number RPLAB @ s @ Serial 473
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Author Siddiqi, I.; Prober, D. E.
Title Nb–Au bilayer hot-electron bolometers for low-noise THz heterodyne detection Type Journal Article
Year 2004 Publication Applied Physics Letters Abbreviated Journal Appl. Phys. Lett.
Volume 84 Issue 8 Pages 1404
Keywords (up) HEB, mixers, dynamic range, saturation, LO power, local oscillator power, Nb
Abstract The sensitivity of present Nb diffusion-cooled hot-electron bolometer (HEB) mixers is not quantum limited, and can be improved by reducing the superconducting transition temperature TC. Lowering TC reduces thermal fluctuations, resulting in a decrease of the mixer noise temperature TM. However, lower TC mixers have reduced dynamic range and saturate more easily due to background noise. We present 30 GHz microwave measurements on a bilayer HEB system, Nb–Au, in which TC can be tuned with Au layer thickness to obtain the maximum sensitivity for a given noise background. These measurements are intended as a guide for the optimization of THz mixers. Using a Nb–Au mixer with TC = 1.6 K, we obtain TM = 50 K with 2 nW of local oscillator (LO) power. Good mixer performance is observed over a wide range of LO power and bias voltage and such a device should not exhibit saturation in a THz receiver.
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ISSN 0003-6951 ISBN Medium
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Notes Approved no
Call Number Serial 571
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Author Semenov, A. D.; Nebosis, R. S.; Gousev, Yu. P.; Heusinger, M. A.; Renk, K. F.
Title Analysis of the nonequilibrium photoresponse of superconducting films to pulsed radiation by use of a two-temperature model Type Journal Article
Year 1995 Publication Phys. Rev. B Abbreviated Journal Phys. Rev. B
Volume 52 Issue 1 Pages 581-590
Keywords (up) HEB, NbN phonon scecific heat, Cp
Abstract Photoresponse of a superconducting film in the resistive state to pulsed radiation has been studied in the framework of a model assuming that two different effective temperatures can be assigned to the quasiparticle and phonon nonequilibrium distributions. The coupled electron-phonon-substrate system is described by a system of time-dependent energy-balance differential equations for effective temperatures. An analytical solution of the system is given and calculated voltage transients are compared with experimental photoresponse signals taking into account the radiation pulse shape and the time resolution of the readout electronics. It is supposed that a resistive state (vortices, fluxons, network of intergrain junctions, hot spots, phase slip centers) provides an ultrafast connection between electron temperature changes and changes of the film resistance and thus plays a minor role in the temporal evolution of the response. In accordance with experimental observations a two-component response was revealed from simulations. The slower component corresponds to a bolometric mechanism while the fast component is connected with the relaxation of the electron temperature. Calculated photoresponse transients are presented for different ratios of the electron and phonon specific heat, radiation pulse durations and fluences, and frequency band passes of registration electronics. From the amplitude of the bolometric component we determine the radiation energy absorbed in a film. This enables us to reveal an intrinsic electron-phonon scattering time even if it is much shorter than the time resolution of readout electronics. We analyze experimental voltage transients for NbN, YBa2Cu3O7, and TlBa2Ca2Cu3O9 superconducting films and find the electron-phonon interaction times at the transition temperatures of 17, 2.5, and 1.8 ps, respectively. The values are in reasonable agreement with data of other experiments.
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Notes Approved no
Call Number Serial 903
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Author Smirnov, A. V.; Larionov, P. A.; Finkel, M. I.; Maslennikov, S. N.; Voronov, B. M.; Gol'tsman, G. N.
Title NbZr films for THz phonon-cooled HEB mixers Type Conference Article
Year 2008 Publication Proc. 19th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 19th Int. Symp. Space Terahertz Technol.
Volume Issue Pages 44-47
Keywords (up) HEB, NbZr, material search
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Corporate Author Thesis
Publisher Place of Publication Groningen, Netherlands Editor
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Notes Approved no
Call Number Serial 577
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Author Tret'yakov, I. V.; Kaurova, N. S.; Voronov, B. M.; Anfert'ev, V. A.; Revin, L. S.; Vaks, V. L.; Gol'tsman, G. N.
Title The influence of the diffusion cooling on the noise band of the superconductor NbN hot-electron bolometer operating in the terahertz range Type Journal Article
Year 2016 Publication Tech. Phys. Lett. Abbreviated Journal
Volume 42 Issue 6 Pages 563-566
Keywords (up) HEB, noise bandwidth, conversion gain bandwidth, noise temperature, Andreev reflection
Abstract Results of an experimental study of the noise temperature (Tn) and noise bandwidth (NBW) of the superconductor NbN hot-electron bolometer (HEB) mixer as a function of its temperature (Tb) are presented. It was determined that the NBW of the mixer is significantly wider at temperatures close to the critical ones (Tc) than are values measured at 4.2 K. The NBW of the mixer measured at the heterodyne frequency of 2.5 THz at temperature Tb close to Tc was ~13 GHz, as compared with 6 GHz at Tb = 4.2 K. This experiment clearly demonstrates the limitation of the thermal flow from the NbN bridge at Tb â‰<aa> Tc for mixers manufactured by the in situ technique. This limitation is close in its nature to the Andreev reflection on the superconductor/ metal boundary. In this case, the noise temperature of the studied mixer increased from 1100 to 3800 K.
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Notes Approved no
Call Number Serial 1106
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