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Author Hajenius, M.; Yang, Z. Q.; Gao, J. R.; Baselmans, J. J. A.; Klapwijk, T. M.; Voronov, B.; Gol'tsman, G.
Title Optimized sensitivity of NbN hot electron bolometer mixers by annealing Type Journal Article
Year 2007 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.
Volume (up) 17 Issue 2 Pages 399-402
Keywords NbN HEB mixers
Abstract We report that the heterodyne sensitivity of superconducting hot-electron bolometers (HEBs) increases by 25-30% after annealing at 85degC in high vacuum. The devices studied are twin-slot antenna coupled mixers with a small area NbN bridge of 1 mum times 0.15 mum, above which there is a SiO 2 passivation layer. The mixer noise temperature, gain, and resistance versus temperature curve of a HEB before and after annealing are compared and analysed. We show that the annealing reduces the intrinsic noise of the mixer by 37% and makes the superconducting transition of the bridge and the contacts sharper. We argue that the reduction ofthe noise is mainly due to the improvement of the transparency of the contact/film interface. The lowest receiver noise temperature of 700 K is measured at a local oscillator frequency of 1.63 THz and at a bath temperature of 4.2 K.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1051-8223 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1426
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Author Ryabchun, S.; Tong, C.-Y. E.; Blundell, R.; Kimberk, R.; Gol'tsman, G.
Title Study of the effect of microwave radiation on the operation of HEB mixers in the terahertz frequency range Type Journal Article
Year 2007 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.
Volume (up) 17 Issue 2 Pages 391-394
Keywords NbN HEB mixers
Abstract We have investigated the effect of injecting microwave radiation, with a frequency much lower than that corresponding to the energy gap of the superconductor, on the performance of the hot-electron bolometer mixer incorporated into a THz heterodyne receiver. More specifically, we show that exposing the mixer to microwave radiation does not cause a significant rise of the receiver noise temperature and fall of the mixer conversion gain so long as the microwave power is a small fraction of local oscillator power. The injection of a small, but controlled amount of microwave power therefore enables active compensation of local oscillator power and coupling fluctuations which can significantly degrade the gain stability of hot electron bolometer mixer receivers.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1051-8223 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1427
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Author Jiang, L.; Antipov, S. V.; Voronov, B. M.; Gol'tsman, G. N.; Zhang, W.; Li, N.; Lin, Z. H.; Yao, Q. J.; Miao, W.; Shi, S. C.; Svechnikov, S. I.; Vakhtomin, Y. B.
Title Characterization of the performance of a quasi-optical NbN superconducting HEB mixer Type Journal Article
Year 2007 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.
Volume (up) 17 Issue 2 Pages 395-398
Keywords NbN HEB mixers, noise temperature
Abstract In this paper we focus mainly on the investigation of the performance of a quasi-optical (planar log-spiral antenna) phonon-cooled NbN superconducting hot electron bolometer (HEB) mixer, which is cryogenically cooled by a close-cycled 4-K cryocooler, at 500 and 850 GHz frequency bands. The mixer's noise performance, stability of IF output power, and local oscillator (LO) power requirement are characterized for three NbN superconducting HEB devices of different sizes. The transmission characteristics of Mylar and Zitex films with incidence waves of an elliptical polarization are also examined by measuring the mixer's noise temperature. The lowest receiver noise temperatures (with no corrections) of 750 and 1100 K are measured at 500 and 850 GHz, respectively. Experimental results also demonstrate that the bigger the HEB device is, the higher the stability of IF output power becomes.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1051-8223 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1429
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Author Gousev, Y. P.; Gol'tsman, G. N.; Karasik, B. S.; Gershenzon, E. M.; Semenov, A. D.; Barowski, H. S.; Nebosis, R. S.; Renk, K. F.
Title Quasioptical superconducting hot electron bolometer for submillmeter waves Type Journal Article
Year 1996 Publication Int. J. of Infrared and Millimeter Waves Abbreviated Journal Int. J. of Infrared and Millimeter Waves
Volume (up) 17 Issue 2 Pages 317-331
Keywords NbN HEB
Abstract We report on a superconducting hot electron bolometer coupled to radiation via a broadband antenna. The bolometer, a structured NbN film, was patterned on a thin dielectric membrane between terminals of a gold slotline antenna. We investigated the response to submillimeter radiation (wave-lengths ∼ 0.1 mm to 0.7 mm) in the fundamental Gaussian mode. We found that the directivity of the antenna was constant within a factor of 2.5 through the whole experimental range. The noise equivalent power of the bolometer at 119 µm was ∼ 3 · 10−13 W/Hz1/2; a time constant of ∼ 160 ps was estimated.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0195-9271 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1618
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Author Semenov, A. D.; Il'in, K.; Siegel, M.; Smirnov, A.; Pavlov, S.; Richter, H.; Hübers, H.-W.
Title Evidence of non-bolometric mixing in the bandwidth of a hot-electron bolometer Type Journal Article
Year 2006 Publication Superconductor Science and Technology Abbreviated Journal Supercond. Sci. Technol.
Volume (up) 19 Issue 10 Pages 1051-1056
Keywords HEB
Abstract
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0953-2048 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 536
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Author Ryabchun, Sergey; Tong, Cheuk-Yu Edward; Blundell, Raymond; Gol'tsman, Gregory
Title Stabilization scheme for hot-electron bolometer receivers using microwave radiation Type Journal Article
Year 2009 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.
Volume (up) 19 Issue 1 Pages 14-19
Keywords HEB, mixer, Allan variance, stabilization, radiometer equation
Abstract We present the results of a stabilization scheme for terahertz receivers based on NbN hot-electron bolometer (HEB) mixers that uses microwave radiation with a frequency much lower than the gap frequency of NbN to compensate for mixer current fluctuations. A feedback control loop, which actively controls the power level of the injected microwave radiation, has successfully been implemented to stabilize the operating point of the HEB mixer. This allows us to increase the receiver Allan time to 10 s and also improve the temperature resolution of the receiver by about 30% in the total power mode of operation.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1051-8223 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number RPLAB @ lobanovyury @ Serial 559
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Author Ryabchun, Sergey; Tong, Cheuk-Yu Edward; Paine, Scott; Lobanov, Yury; Blundell, Raymond; Goltsman, Gregory
Title Temperature resolution of an HEB receiver at 810 GHz Type Journal Article
Year 2009 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.
Volume (up) 19 Issue 3 Pages 293-296
Keywords HEB mixer
Abstract We present the results of direct measurements of the temperature resolution of an HEB receiver operating at 810 GHz, in both continuum and spectroscopic modes. In the continuum mode, the input of the receiver was switched between black bodies with different physical temperatures. With a system noise temperature of around 1100 K, the receiver was able to resolve loads which differed in temperature by about 1 K over an integration time of 5 seconds. This resolution is significantly worse than the value of 0.07 K given by the radiometer equation. In the spectroscopic mode, a gas cell filled with carbonyl sulphide (OCS) gas was used and the emission line at 813.3537060 GHz was measured using the receiver in conjunction with a digital spectrometer. From the observed spectra, we determined that the measurement uncertainty of the equivalent emission temperature was 2.8 K for an integration time of 0.25 seconds and a spectral resolution of 12 MHz, compared to a 1.4 K temperature resolution given by the radiometer equation. This relative improvement is due to the fact that at short integration times the contribution from 1/f noise and drift are less dominant. In both modes, the temperature resolution was improved by about 40% with the use of a feedback loop which adjusted the level of an injected microwave radiation to maintain a constant operating current of the HEB mixer. This stabilization scheme has proved to be very effective to keep the temperature resolution of the HEB receiver to close to the theoretical value given by the radiometer equation.
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Notes Approved no
Call Number Serial 636
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Author Yang, Z. Q.; Hajenius, M.; Baselmans, J. J. A.; Gao, J. R.; Voronov, B.; Gol’tsman, G. N.
Title Reduced noise in NbN hot-electron bolometer mixers by annealing Type Journal Article
Year 2006 Publication Supercond. Sci. Technol. Abbreviated Journal Supercond. Sci. Technol.
Volume (up) 19 Issue 4 Pages L (9 to 12)
Keywords NbN HEB mixers
Abstract We find that the sensitivity of heterodyne receivers based on superconducting hot-electron bolometers (HEBs) increases by 25–30% after annealing at 85 °C in vacuum. The devices studied are twin-slot antenna coupled mixers with a small NbN bridge of 1 × 0.15 µm2. We show that annealing changes the device properties as reflected in sharper resistive transitions of the complete device, apparently reducing the device-related noise. The lowest receiver noise temperature of 700 K is measured at a local oscillator frequency of 1.63 THz and a bath temperature of 4.3 K.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0953-2048 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1456
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Author Tretyakov, Ivan; Ryabchun, Sergey; Finkel, Matvey; Maslennikov, Sergey; Maslennikova, Anna; Kaurova, Natalia; Lobastova, Anastasia; Voronov, Boris; Gol'tsman, Gregory
Title Ultrawide noise bandwidth of NbN hot-electron bolometer mixers with in situ gold contacts Type Journal Article
Year 2011 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal
Volume (up) 21 Issue 3 Pages 620-623
Keywords NbN HEB mixer bandwidth
Abstract We report a noise bandwidth of 7 GHz in the new generation of NbN hot-electron bolometer (HEB) mixers that are being developed for the space observatory Millimetron. The HEB receiver driven by a 2.5-THz local oscillator offered a noise temperature of 600 K in a 50-MHz final detection bandwidth. As the filter center frequency was swept this value remained nearly constant up to the cutoff frequency of the cryogenic amplifier at 7 GHz. We believe that such a low value of the noise temperature is due to reduced radio frequency (RF) loss at the interface between the superconducting film and the gold contacts. We have also performed gain bandwidth measurements at the superconducting transition on HEB mixers with various lengths and found them to be in excellent agreement with the results of the analytical and numerical models developed for the HEB mixer with both diffusion and phonon cooling of hot electrons.
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Notes Approved no
Call Number RPLAB @ gujma @ Serial 716
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Author Lobanov, Y.; Tong, E.; Blundell, R.; Hedden, A.; Voronov, B.; Gol'tsman, G.
Title Large-signal frequency response of an HEB mixer: from 300 MHz to terahertz Type Journal Article
Year 2011 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal
Volume (up) 21 Issue 3 Pages 628-631
Keywords waveguide NbN HEB mixers
Abstract We present a study of the large signal frequency response of an HEB mixer over a wide frequency range. In our experiments, we have subjected the HEB mixer to incident electromagnetic radiation from 0.3 GHz to 1 THz. The mixer element is an NbN film deposited on crystalline quartz. The mixer chip is mounted in a waveguide cavity, coupled to free space with a diagonal horn. At microwave frequencies, electromagnetic radiation is applied through the coaxial bias port of the mixer block. At higher frequencies the input signal passes via the diagonal horn feed. At each frequency, the incident power is varied and a family of I-V curves is recorded. From the curves we identify 3 distinct regimes of operation of the mixer separated by the phonon relaxation frequency and the superconducting energy gap frequency observed at about 3 GHz and 660 GHz respectively. In this paper, we will present observed curves and discuss the results of our experiment.
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Language Summary Language Original Title
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Notes Approved no
Call Number RPLAB @ gujma @ Serial 719
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