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Author Gao, J.R.; Hiajenius, M.; Yang, Z.Q.; Klapwijk, T.M.; Miao, W.; Shi, S. C.; Voronov, B.; Gortsman, G.
Title (up) Direct comparison of the sensitivity of a spiral and a twin-slot antenna coupled HEB mixer at 1.6 THz Type Conference Article
Year 2006 Publication Proc. 17th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 17th Int. Symp. Space Terahertz Technol.
Volume Issue Pages 59-62
Keywords NbN HEB mixers
Abstract To make a direct comparison of the sensitivity between a spiral and a twin slot antenna coupled HEB mixer, we designed both types of mixers and fabricated them in a single processing run and on the same wafer. Both mixers have similar dimensions of NbN bridges (1.5-2 pm x0.2 pm). At 1.6 THz we obtained a nearly identical receiver noise temperature from both mixers (only 5% difference), which is in a good agreement with the simulation based on semi analytical models for both antennas. In addition, by using a bandpass filter to reduce the direct detection effect and lowering the bath temperature to 2.4 K, we measured the lowest receiver noise temperature of 700 K at 1.63 THz using the twin-slot antenna mixer.
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Call Number Serial 1436
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Author Baryshev, A.; Baselmans, J. J. A.; Reker, S. F.; Hajenius, M.; Gao, J. R.; Klapwijk, T. M.; Vachtomin, Yu.; Maslennikov, S.; Antipov, S.; Voronov, B.; Gol'tsman, G.
Title (up) Direct detection effect in hot electron bolometer mixers Type Abstract
Year 2005 Publication Proc. 16th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 16th Int. Symp. Space Terahertz Technol.
Volume Issue Pages 463-464
Keywords NbN HEB mixers, effect of direct detection, direct detection effect
Abstract NbN phonon cooled hot electron bolometer (HEB) mixers are currently the most sensitive heterodyne detectors at frequencies above 1.2 THz. They combine a good sensitivity (8-15 times the quantum limit), an IF bandwidth of the order of 4-6 GHz and a wide RF bandwidth from 0.7-5.2 THz. However, for use in a space based observatory, such as Herschel, it is of vital importance that the Local Oscillator (LO) power requirement of the mixer is compatible with the low output power of present day THz LO sources. This can be achieved by reducing the mixer volume and critical current. However, the large RF bandwidth and low LO power requirement of such a mixer result in a direct detection effect, characterized by a change in the bias current of the HEB when changing the RF signal from a black body load at 300 K to one at 77 K. As a result the measured sensitivity using a 300 K and 77 K calibration load differs significantly from the small signal sensitivity relevant for astronomical observations. In this article we describe a set of dedicated experiments to characterize the direct detection effect for a small volume quasi-optical NbN phonon cooled HEB mixer. We measure the direct detection effect in a small volume (0.15 μm · 1 μm · 3.5 nm) quasi- optical NbN phonon cooled HEB mixer at 1.6 THz. We found that the small signal sensitivity of the receiver is underestimated by approximately 35% due to the direct detection effect and that the optimal operating point is shifted to higher bias voltages when using calibration loads of 300 K and 77 K. Using a 200 GHz wide band-pass filter at the 4.2 K the direct detection effect virtually disappears. Heterodyne response measurements using water vapor absorption line in a gas cell confirms the existence and a magnitude of a direct detection effect. We also propose a theoretical explanation using uniform electron heating model. This direct detection effect has important implications for the calibration procedure of these receivers in real telescope systems. We are developing Nb HEBs for a large-format, diffusion-cooled hot electron bolometer (HEB) array submillimeter camera. The goal is to produce a 64 pixel array together with the University of Arizona to be used on the HHT on Mt Graham. It is designed to detect in the 850 GHz atmospheric window. We have fabricated Nb HEBs using a new angle- deposition process, which had previously produced high quality Nb-Au bilayer HEB devices at Yale. [1] We have characterized these devices using heterodyne mixing at ~30 GHz to compare to 345 GHz tests at the University of Arizona. We can also directly compare our Nb HEB mixers to SIS mixers in this same 345 GHz system. This allows us to rigorously calibrate the system’s losses and extract the mixer noise temperature in a well characterized mixer block, before undertaking the 850 GHz system. Here we give a report on the initial devices we have fabricated and characterized. * Department of Applied Physics, Yale University ** Department of Astronomy, University of Arizona [1] Applied Physics Letters 84, Number 8; p.1404-7, Feb 23 (2004)
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Call Number Serial 1475
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Author Baselmans, J. J. A.; Baryshev, A.; Reker, S. F.; Hajenius, M.; Gao, J. R.; Klapwijk, T. M.; Vahtomin, Yu.; Maslennikov, S.; Antipov, S.; Voronov, B.; Gol'tsman, G.
Title (up) Direct detection effect in small volume hot electron bolometer mixers Type Journal Article
Year 2005 Publication Appl. Phys. Lett. Abbreviated Journal Appl. Phys. Lett.
Volume 86 Issue 16 Pages 163503 (1 to 3)
Keywords HEB, mixer, direct detection effect
Abstract We measure the direct detection effect in a small volume (0.15μm×1μm×3.5nm)(0.15μm×1μm×3.5nm) quasioptical NbN phonon cooled hot electronbolometermixer at 1.6THz1.6THz. We find that the small signal sensitivity of the receiver is underestimated by 35% due to the direct detection effect and that the optimal operating point is shifted to higher bias voltages when using calibration loads of 300K300K and 77K77K. Using a 200GHz200GHzbandpass filter at 4.2K4.2K the direct detection effect virtually disappears. This has important implications for the calibration procedure of these receivers in real telescope systems.
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Notes Approved no
Call Number Serial 377
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Author Kitaeva, G. K.; Kornienko, V. V.; Kuznetsov, K. A.; Pentin, I. V.; Smirnov, K. V.; Vakhtomin, Y. B.
Title (up) Direct detection of the idler THz radiation generated by spontaneous parametric down-conversion Type Journal Article
Year 2019 Publication Opt. Lett. Abbreviated Journal Opt. Lett.
Volume 44 Issue 5 Pages 1198-1201
Keywords HEB applications
Abstract We study parametric down-conversion (PDC) of optical laser radiation in the strongly frequency non-degenerate regime which is promising for the generation of quantum-correlated pairs of extremely different spectral ranges, the optical and the terahertz (THz) ones. The possibility to detect tenuous THz-frequency photon fluxes generated under low-gain spontaneous PDC is demonstrated using a hot electron bolometer. Then experimental dependences of the THz radiation power on the detection angle and on the pump intensity are analyzed.
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Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0146-9592 ISBN Medium
Area Expedition Conference
Notes PMID:30821747 Approved no
Call Number Serial 1801
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Author Lobanov, Y.V.; Tong, C.-Y.E.; Hedden, A.S.; Blundell, R.; Voronov, B.M.; Gol'tsman, G.N.
Title (up) Direct measurement of the gain and noise bandwidths of HEB mixers Type Journal Article
Year 2011 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.
Volume 21 Issue 3 Pages 645-648
Keywords waveguide NbN HEB mixers
Abstract The intermediate frequency (IF) bandwidth of a hot electron bolometer (HEB) mixer is an important parameter of the mixer, in that it helps to determine its suitability for a given application. With the availability of wideband low noise amplifiers, it is simple to measure the performance of an HEB mixer over a wide range of IF at a fixed LO frequency using the standard Y-factor method. This in-situ method allows us to measure both the gain and noise bandwidths simultaneously. We have also measured mixer output impedance with a vector network analyser. Intrinsic time constant has been extracted from the impedance data and compared to the mixer's bandwidths determined from receiver Y-factor measurement.
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Notes Approved no
Call Number RPLAB @ gujma @ Serial 720
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Author Verevkin, A. A.; Ptitsina, N. G.; Smirnov, K. V.; Goltsman, G. N.; Gershenson, E. M.; Yngvesson, K. S.
Title (up) Direct measurements of electron energy relaxation times at an AlGaAs/GaAs heterointerface in the optical phonon scattering range Type Conference Article
Year 1997 Publication Proc. 4-th Int. Semicond. Device Research Symp. Abbreviated Journal Proc. 4-th Int. Semicond. Device Research Symp.
Volume Issue Pages 55-58
Keywords 2DEG, AlGaAs/GaAs heterostructures
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Call Number Serial 1602
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Author Verevkin, A. A.; Ptitsina, N. G.; Chulcova, G. M.; Gol'tsman, G. N.; Gershenzon, E. M.; Yngvesson, K. S.
Title (up) Direct measurements of energy relaxation time of electrons in AlGaAs/GaAs heterostructures under quasi-equilibrium conditions Type Journal Article
Year 1996 Publication Surface Science Abbreviated Journal Surface Science
Volume 361-362 Issue Pages 569-573
Keywords 2DEG, AlGaAs/GaAs heterostructures
Abstract For the first time, results are presented of a direct measurement of the energy relaxation time τε of 2D electrons in an AlGaAs/GaAs heterojunction at T = 1 and 5–20 K. A weak temperature dependence of τε for the T > 4K range and a linear temperature dependence of the reciprocal of τε for T < 4K have been observed. The linear dependence τε−1 ≈ T in the Bloch-Gruneisen regime is direct evidence of the predominance of the piezo-electric mechanism of electron-phonon interaction in non-elastic electron scattering processes. The values of τε in this regime are in very good agreement with the results of the Karpus theory. At higher temperatures, where the deformation-potential scattering becomes noticeable, a substantial disagreement between the experimental data and the theoretical results is observed.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0039-6028 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1609
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Author Verevkin, A.; Gershenzon, E. M.; Gol'tsman, G. N.; Ptitsina, N. G.; Chulkova, G. M.; Smirnov, K. S.; Sobolewski, R.
Title (up) Direct measurements of energy relaxation times in two-dimensional structures under quasi-equilibrium conditions Type Conference Article
Year 2002 Publication Mater. Sci. Forum Abbreviated Journal Mater. Sci. Forum
Volume 384-3 Issue Pages 107-116
Keywords 2DEG, AlGaAs/GaAs
Abstract A new microwave technique was successfully applied for direct studies of energy relaxation times in two-dimensional AlGaAs/GaAs structures under quasi-equilibrium conditions in the nanosecond and picosecond time scale. We report our results of energy relaxation time measurements in the temperature range 1.6-50 K, in quantum Hall effect regime in magnetic fields up to 4 T.
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Area Expedition Conference Materials Science Forum
Notes Approved no
Call Number Serial 1536
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Author Verevkin, A. A.; Ptitsina, N. G.; Smirnov, K. V.; Gol’tsman, G. N.; Gershenzon, E. M.; Ingvesson, K. S.
Title (up) Direct measurements of energy relaxation times on an AlGaAs/GaAs heterointerface in the range 4.2–50 K Type Journal Article
Year 1996 Publication JETP Lett. Abbreviated Journal JETP Lett.
Volume 64 Issue 5 Pages 404-409
Keywords 2DEG, AlGaAs/GaAs heterostructures
Abstract The temperature dependence of the energy relaxation time τe (T) of a two-dimensional electron gas at an AlGaAs/GaAs heterointerface is measured under quasiequilibrium conditions in the region of the transition from scattering by acoustic phonons to scattering with the participation of optical phonons. The temperature interval of constant τe, where scattering by the deformation potential predominates, is determined. In the preceding, low-temperature region, where piezoacoustic and deformation-potential-induced scattering processes coexist, τ e decreases slowly with increasing temperature. Optical phonons start to participate in the scattering processes at T∼25 K (the characteristic phonon lifetime was equal to τLOτ4.5 ps). The energy losses calculated from the τe data in a model with an effective nonequilibrium electron temperature agree with the published data obtained under strong heating conditions.
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Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-3640 ISBN Medium
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Notes http://jetpletters.ru/ps/981/article_14955.shtml (“Прямые измерения времен энергетической релаксации на гетерогранице AlGaAs/GaAs в диапазоне 4.2 – 50 К”) Approved no
Call Number Serial 1608
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Author Baselmans, J. J. A.; Hajenius, M.; Gao, J. R.; Klapwijk, T. M.; de Korte, P. A. J.; Voronov, B.; Gol'tsman, G.
Title (up) Doubling of sensitivity and bandwidth in phonon cooled hot electron bolometer mixers Type Journal Article
Year 2004 Publication Appl. Phys. Lett. Abbreviated Journal Appl. Phys. Lett.
Volume 84 Issue 11 Pages 1958-1960
Keywords NbN HEB mixers
Abstract We demonstrate that the performance of NbN lattice cooled hot electron bolometer mixers depends strongly on the interface quality between the bolometer and the contact structure. We show experimentally that both the receiver noise temperature and the gain bandwidth can be improved by more than a factor of 2 by cleaning the interface and adding an additional superconducting interlayer to the contact pad. Using this we obtain a double sideband receiver noise temperature TN,DSB=950 K

at 2.5 THz and 4.3 K, uncorrected for losses in the optics. At the same bias point, we obtain an IF gain bandwidth of 6 GHz.
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Notes Approved no
Call Number Serial 352
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