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Author Ryabchun, Sergey; Tong, Cheuk-Yu Edward; Paine, Scott; Lobanov, Yury; Blundell, Raymond; Goltsman, Gregory
Title (up) 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 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 Karpowicz, Nicholas; Lu, Xiaofei; Zhang, X.-C.
Title (up) Terahertz gas photonics Type Journal Article
Year 2009 Publication J. Modern Opt. Abbreviated Journal
Volume 56 Issue 10 Pages 1137-1150
Keywords
Abstract The underlying physics of the generation and detection of terahertz (THz) waves in gases are described. The THz wave generation process takes place in two steps: asymmetric gas ionization by two-frequency laser fields, followed by interaction of the ionized electron wave packets with the surrounding medium, producing an intense ‘echo' with tunable spectral content. In order to clarify the physical picture at the moment of ionization, the laser–atom interaction is treated through solution of the time-dependent Schrödinger equation, yielding an ab initio understanding of the release of the electron wave packets. The second step, where the electrons interact with the surrounding plasma is treated analytically. The resulting pressure dependence of the THz radiation is explored in detail. The THz wave detection process is shown to be the result of four-wave mixing, leading to analytical expressions of the signal obtained which allow for improved optimization of systems that exploit these effects.
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Call Number RPLAB @ gujma @ Serial 670
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Author Hübers, H.-W.; Semenov, A.; Richter, H.; Birk, M.; Krocka, M.; Mair, U.; Smirnov, K.; Gol’tsman, G.; Voronov, B.
Title (up) Terahertz Heterodyn Receiver with a hot-electron bolometer mixer Type Conference Article
Year 2002 Publication Far-IR, Sub-mm & MM Detector Technology Workshop Abbreviated Journal Far-IR, Sub-mm & MM Detector Technology Workshop
Volume Issue Pages 3-24
Keywords NbN HEB mixers
Abstract During the past decade major advances have been made regarding low noise mixers for terahertz (THz) heterodyne receivers. State of the art hot-electron-bolometer (HEB) mixers have noise temperatures close to the quantum limit and require less than a µW power from the local oscillator (LO). The technology is now at a point where the performance of a practical receiver employing such mixer, rather than the figures of merit of the mixer itself, are of major concern. We have incorporated a phonon-cooled NbN HEB mixer in a 2.5 THz heterodyne receiver and investigated the performance of the receiver. This yields important information for the development of heterodyne receivers such as GREAT (German receiver for astronomy at THz frequencies aboard SOFIA) [1] and TELIS (Terahertz limb sounder), a balloon borne heterodyne receiver for atmospheric research [2]. Both are currently under development at DLR.
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Publisher NASA Place of Publication Editor Wolf, U.; Farhoomand, J.; McCreight, C.R.
Language Summary Language Original Title
Series Editor Series Title NASA CP Abbreviated Series Title
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Notes Volume: 211408 Approved no
Call Number Serial 1537
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Author Cherednichenko, S.; Drakinskiy, V.; Lecomte, B.; Dauplay, F.; Krieg, J.-M.; Delorme, Y.; Feret, A.; Hübers, H.-W.; Semenov, A.D.; Gol’tsman, G.N.
Title (up) Terahertz heterodyne array based on NbN HEB mixers Type Abstract
Year 2008 Publication Proc. 19th Int. Symp. Space Terahertz Technol. Abbreviated Journal
Volume Issue Pages 43
Keywords NbN HEB mixers array
Abstract A 16 pixel heterodyne receiver for 2.5 THz is been developed based on NbN superconducting hot-electron bolometer (HEB) mixers. The receiver uses a quasioptical RF coupling approach where HEB mixers are integrated into double dipole antennas on 1.5μm thick Si3N4 / SiO2 membranes. Miniature mirrors (one per pixel) and back short for the antenna were used to design the output mixer beam profile. The camera design allows all 16 pixel IF readout in parallel. The gain bandwidth of the HEB mixers on Si3N4 / SiO 2 membranes was found to be about 3 GHz, when an MgO buffer layers is applied on the membrane. We will also present the progress in the camera heterodyne tests.
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Notes Approved no
Call Number Serial 1411
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Author Hübers, H.-W.; Semenov, A.; Richter, H.; Birk, Manfred; Krocka, Michael; Mair, Ulrich; Smirnov, K.; Gol'tsman, G.; Voronov, B.
Title (up) Terahertz heterodyne receiver with a hot-electron bolometer mixer Type Conference Article
Year 2002 Publication Proc. Far-IR, Sub-mm, and mm Detector Technology Workshop Abbreviated Journal Proc. Far-IR, Sub-mm, and mm Detector Technology Workshop
Volume Issue Pages
Keywords NbN HEB mixers
Abstract During the past decade major advances have been made regarding low noise mixers for terahertz (THz) heterodyne receivers. State of the art hot-electron-bolometer (HEB) mixers have noise temperatures close to the quantum limit and require less than a µW power from the local oscillator (LO). The technology is now at a point where the performance of a practical receiver employing such mixer, rather than the figures of merit of the mixer itself, are of major concern. We have incorporated a phonon-cooled NbN HEB mixer in a 2.5 THz heterodyne receiver and investigated the performance of the receiver. This yields important information for the development of heterodyne receivers such as GREAT (German receiver for astronomy at THz frequencies aboard SOFIA)[1] and TELIS (Terahertz limb sounder), a balloon borne heterodyne receiver for atmospheric research [2]. Both are currently under development at DLR.
Address Monterey, CA, USA
Corporate Author Thesis
Publisher Place of Publication Editor Wold, J.; Davidson, J.
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Notes 4 pages; Unconfirmed but cited in https://kups.ub.uni-koeln.de/1622/1/bedorf.pdf; There is a Program of the Workshop: https://www.yumpu.com/en/document/view/7411055/far-ir-submm-mm-detector-technology-workshop-sofia-usra (there is no title of this article in the Program); There is also identical publication in Proc. ISSTT (Serial: 332, “A broadband terahertz heterodyne receiver with an NbN HEB mixer”). Approved no
Call Number Serial 1829
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