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Author Trifonov, A.; Tong, C.-Y. E.; Lobanov, Y.; Kaurova, N.; Blundell, R.; Goltsman, G.
Title Gap frequency and photon absorption in a hot electron bolometer Type Conference Article
Year 2016 Publication Proc. 27th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 27th Int. Symp. Space Terahertz Technol.
Volume Issue Pages 121
Keywords NbN HEB; Si membrane
Abstract The superconducting energy gap is a crucial parameter of a superconductor when used in mixing applications. In the case of the SIS mixer, the mixing process is efficient for frequencies below the energy gap, whereas, in the case of the HEB mixer, the mixing process is most efficient at frequencies above the gap, where photon absorption takes place more readily. We have investigated the photon absorption phenomenon around the gap frequency of HEB mixers based on NbN films deposited on silicon membranes. Apart from studying the pumped I-V curves of HEB devices, we have also probed them with microwave radiation, as previously described [1]. At frequencies far below the gap frequency, the pumped I-V curves show abrupt switching between the superconducting and resistive states. For the NbN HEB mixers we tested, which have critical temperatures of ~9 K, this is true for frequencies below about 400 GHz. As the pump frequency is increased beyond 400 GHz, the resistive state extends towards zero bias and at some point a small region of negative differential resistance appears close to zero bias. In this region, the microwave probe reveals that the device impedance is changing randomly with time. As the pump frequency is further increased, this random impedance change develops into relaxation oscillations, which can be observed by the demodulation of the reflected microwave probe. Initially, these oscillations take the form of several frequencies grouped together under an envelope. As we approach the gap frequency, the multiple frequency relaxation oscillations coalesce into a single frequency of a few MHz. The resultant square-wave nature of the oscillation is a clear indication that the device is in a bi-stable state, switching between the superconducting and normal state. Above the gap frequency, it is possible to obtain a pumped I-V curve with no negative differential resistance above a threshold pumping level. Below this pumping level, the device demonstrates bi-stability, and regular relaxation oscillation at a few MHz is observed as a function of pump power. The threshold pumping level is clearly related to the amount of power absorbed by the device and its phonon cooling. From the above experiment, we can derive the gap frequency of the NbN film, which is 585 GHz for our 6 μm thin silicon membrane-based device. We also confirm that the HEB mixer is not an efficient photon absorber for radiation below the gap frequency. 1. A. Trifonov et al., “Probing the stability of HEB mixers with microwave injection”, IEEE Trans. Appl. Supercond., vol. 25, no. 3, June 2015.
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Notes Approved no
Call Number Serial 1204
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Author Tovpeko, N. A.; Trifonov, A. V.; Semenov, A. V.; Antipov, S. V.; Kaurova, N. S.; Titova, N. A.; Goltsman, G. N.
Title Bandwidth performance of a THz normal metal TiN bolometer-mixer Type Conference Article
Year 2019 Publication Proc. 30th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 30th Int. Symp. Space Terahertz Technol.
Volume Issue Pages 102-103
Keywords TiN normal metal bolometer, NMB
Abstract We report on the bandwidth performance of the normal metal TiN bolometer-mixer on top of an Al 2 O 3 substrate, which is capable to operate in a wide range of bath temperatures from 77 K – 300 K. The choice of the combination TiN / Al 2 O 3 is related to an advanced heat transport between the film and the substrate in this pair and the sufficient temperature coefficient of resistance. The data were taken at 132.5 – 145.5 GHz with two BWOs as a signal and an LO source. Measurements were taken on TiN films of different thickness starting from 20 nm down to 5 nm coupled into a spiral Au antenna, which improves matching of incoming radiation with the thin TiN fim. Our experiments demonstrate effective heat coupling from a TiN thin film to an Al 2 O 3 substrate (111) boosting gain bandwidth (GB) of TiN bolometer up to 6 GHz for 5 nm thin film. Current results indicate weak temperature dependence of GB on the bath temperature of the TiN bolometer. Theoretical estimations of GB performance meet with experimental data for 5 nm thin TiN films.
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Area Expedition Conference
Notes Approved no
Call Number Serial 1279
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Author Tretyakov, Ivan; Kaurova, N.; Voronov, B. M.; Goltsman, G. N.
Title About effect of the temperature operating conditions on the noise temperature and noise bandwidth of the terahertz range NbN hot-electron bolometers Type Abstract
Year 2018 Publication Proc. 29th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 29th Int. Symp. Space Terahertz Technol.
Volume Issue Pages 113
Keywords NbN HEB mixer
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) and NbN bridge length 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 ≪ 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 1313
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Author Ryabchun, S.; Smirnov, A.; Pentin, I.; Vakhtomin, Yu.; Smirnov, K.; Kaurova, N.; Voronov, B.; Goltsman, G.
Title Superconducting single photon detector integrated with optical cavity Type Conference Article
Year 2011 Publication Proc. MLPLIT Abbreviated Journal Proc. MLPLIT
Volume Issue Pages 143-145
Keywords NbN SSPD, cavity
Abstract
Address Suzdal / Vladimir (Russia)
Corporate Author Thesis
Publisher Modern laser physics and laser-information technologies for science and manufacture Place of Publication Editor
Language Summary Language Original Title
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ISSN ISBN Medium
Area Expedition Conference 1st international russian-chinese conference / youthschool-workshop
Notes September 23-28, 2011 Approved no
Call Number Serial 1385
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Author Maslennikova, A.; Larionov, P.; Ryabchun, S.; Smirnov, A.; Pentin, I.; Vakhtomin, Yu.; Smirnov, K.; Kaurova, N.; Voronov, B.; Goltsman, G.
Title Noise equivalent power and dynamic range of NBN hot-electron bolometers Type Conference Article
Year 2011 Publication Proc. MLPLIT Abbreviated Journal Proc. MLPLIT
Volume Issue Pages 146-148
Keywords NbN HEB
Abstract
Address Suzdal / Vladimir (Russia)
Corporate Author Thesis
Publisher Modern laser physics and laser-information technologies for science and manufacture Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference 1st international russian-chinese conference / youthschool-workshop
Notes September 23-28, 2011 Approved no
Call Number Serial 1386
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