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Author Ozhegov, R. V.; Okunev, O. V.; Gol’tsman, G. N.; Filippenko, L. V.; Koshelets, V. P.
Title Noise equivalent temperature difference of a superconducting integrated terahertz receiver Type Journal Article
Year 2009 Publication (down) J. Commun. Technol. Electron. Abbreviated Journal J. Commun. Technol. Electron.
Volume 54 Issue 6 Pages 716-720
Keywords SIS mixer SIR NETD, FFO, harmonic mixer
Abstract The dependence of the noise equivalent temperature difference (NETD) of a superconducting integrated receiver (SIR) on the receiver noise temperature and the inputsignal level has been investigated. An unprecedented NETD of 13±2 mK has been measured at a SIR noise temperature of 200 K, intermediate-frequency bandwidth of 4 GHz, and time constant of 1 s. With a decrease in the input signal, an improvement in the NETD is observed. This effect is explained by a reduction in the influence of the instabilities of the receiver power supply and the amplification circuit that occur when the input signal is decreased.
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Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1064-2269 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1400
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Author Meledin, Denis; Pavolotsky, Alexey; Desmaris, Vincent.; Lapkin, Igor; Risacher, Christophe; Perez, Victor; Henke, Douglas; Nystrom, Olle; Sundin, Erik; Dochev, Dimitar; Pantaleev, Miroslav; Fredrixon, Mathias; Strandberg, Magnus; Voronov, Boris; Goltsman, Gregory; Belitsky, Victor
Title A 1.3-THz balanced waveguide HEB mixer for the APEX telescope Type Journal Article
Year 2009 Publication (down) IEEE Trans. Microw. Theory Techn. Abbreviated Journal
Volume 57 Issue 1 Pages 89-98
Keywords HEB, mixer, waveguide, balanced, NbN
Abstract In this paper, we report about the development, fabrication, and characterization of a balanced waveguide hot electron bolometer (HEB) receiver for the Atacama Pathfinder EXperiment telescope covering the frequency band of 1.25–1.39 THz. The receiver uses a quadrature balanced scheme and two HEB mixers, fabricated from 4- to 5-nm-thick NbN film deposited on crystalline quartz substrate with an MgO buffer layer in between. We employed a novel micromachining method to produce all-metal waveguide parts at submicrometer accuracy (the main-mode waveguide dimensions are 90×180 μm). We present details on the mixer design and measurement results, including receiver noise performance, stability and “first-light” at the telescope site. The receiver yields a double-sideband noise temperature averaged over the RF band below 1200 K, and outstanding stability with a spectroscopic Allan time more than 200 s.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0018-9480 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number RPLAB @ lobanovyury @ Serial 554
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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 (down) IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.
Volume 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 (down) IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.
Volume 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 Xiaolong Hu; Holzwarth, C.W.; Masciarelli, D.; Dauler, E.A.; Berggren, K.K.
Title Efficiently coupling light to superconducting nanowire single-photon detectors Type Journal Article
Year 2009 Publication (down) IEEE Trans. Appl. Supercond. Abbreviated Journal
Volume 19 Issue 3 Pages 336-340
Keywords optical antennas; SNSPD
Abstract We designed superconducting nanowire single-photon detectors (SNSPDs) integrated with silver optical antennae for free-space coupling and a dielectric waveguide for fiber coupling. According to our finite-element simulation, (1) for the free-space coupling, the absorptance of the NbN nanowire for TM-polarized photons at the wavelength of 1550 nm can be as high as 96% by adding silver optical antennae; (2) for the fiber coupling, the absorptance of the NbN nanowire for TE-like-polarized photons can reach 76% including coupling efficiency at the wavelength of 1550 nm by adding a silicon nitride waveguide and an inverse-taper coupler.
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Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
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Area Expedition Conference
Notes Approved no
Call Number RPLAB @ gujma @ Serial 647
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