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| Author | Risacher, C.; Meledin, D.; Belitsky, V.; Bergman, P. | ||||
| Title | First 1.3 THz observations at the APEX telescope | Type | Conference Article | ||
| Year | 2009 | Publication | Proc. 20th Int. Symp. Space Terahertz Technol. | Abbreviated Journal  |
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| Volume | Issue | Pages | 54-61 | ||
| Keywords | balanced HEB mixer noise temperature APEX telescope stability Allan variance aperture efficiency | ||||
| Abstract | The Atacama Pathfinder EXperiment (APEX) 12m telescope is operating on the Llano Chajnantor, Chile, since 2003 and a set of state of the art sub-millimeter receivers have been installed for frequencies spanning from 150 GHz to 1500 GHz. In 2008, a balanced 1.3 THz Hot Electron Bolometer (HEB) receiver was installed for the atmospheric window 1250-1380 GHz. This instrument is part of a 4-channel receiver cryostat with the other channels being 211-275 GHz, 275-370 GHz and 380-500 GHz Sideband Separating (SSB) SIS receivers. This paper presents the first observations obtained so far with the 1.3 THz band during its first months of operation. The sky measurements were taken during opportunistic commissioning and science verification phases, when the weather conditions were sufficiently good with a Precipitable Water Vapor (PWV) below 0.25 mm, which was the case only a few nights during these months. We present the first observations of the molecular transition CO J=(11-10) line on different sources such as Orion-FIR4, CW-Leo and SgrB2(M). We describe the many challenges and difficulties encountered for achieving successful THz observations from a large sub-millimeter ground-based telescope. | ||||
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| Notes | Approved | no | |||
| Call Number | Serial | 619 | |||
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| Author | Huebers, Heinz-Wilhelm; Pavlov, S.; Semenov, A.; Köhler, R.; Mahler, L.; Tredicucci, A.; Beere, H.; Ritchie, D.; Linfield, E. | ||||
| Title | Terahertz quantum cascade laser as local oscillator in a heterodyne receiver | Type | Journal Article | ||
| Year | 2005 | Publication | Optics Express | Abbreviated Journal |
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| Volume | 13 | Issue | 15 | Pages | 5890-5896 |
| Keywords | QCL heterodyne, 6 mW at 2.5 THz, HEB mixer, terahertz | ||||
| Abstract | Terahertz quantum cascade lasers have been investigated with respect to their performance as a local oscillator in a heterodyne receiver. The beam profile has been measured and transformed in to a close to Gaussian profile resulting in a good matching between the field patterns of the quantum cascade laser and the antenna of a superconducting hot electron bolometric mixer. Noise temperature measurements with the hot electron bolometer and a 2.5 THz quantum cascade laser yielded the same result as with a gas laser as local oscillator. | ||||
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| Notes | Approved | no | |||
| Call Number | Serial | 627 | |||
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| Author | Rabanus, D.; Graf, U. U.; Philipp, M.; Ricken, O.; Stutzki, J.; Vowinkel, B.; Wiedner, M. C.; Walther, C.; Fischer, M.; Faist, J. | ||||
| Title | Phase locking of a 1.5 terahertz quantum cascade laser and use as a local oscillator in a heterodyne HEB receiver | Type | Journal Article | ||
| Year | 2009 | Publication | Optics Express | Abbreviated Journal |
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| Volume | 17 | Issue | 3 | Pages | 1159-1168 |
| Keywords | QCL heterodyne, 300 uW at 1.5 THz, HEB mixer | ||||
| Abstract | We demonstrate for the first time the closure of an electronic phase lock loop for a continuous–wave quantum cascade laser (QCL) at 1.5 THz. The QCL is operated in a closed cycle cryo cooler. We achieved a frequency stability of better than 100 Hz, limited by the resolution bandwidth of the spectrum analyser. The PLL electronics make use of the intermediate frequency (IF) obtained from a hot electron bolometer (HEB) which is downconverted to a PLL IF of 125 MHz. The coarse selection of the longitudinal mode and the fine tuning is achieved via the bias voltage of the QCL. Within a QCL cavity mode, the free-running QCL shows frequency fluctuations of about 5 MHz, which the PLL circuit is able to control via the Stark–shift of the QCL gain material. Temperature dependent tuning is shown to be nonlinear, and of the order of -16 MHz/K. Additionally we have used the QCL as local oscillator (LO) to pump an HEB and perform, again for the first time at 1.5 THz, a heterodyne experiment, and obtain a receiver noise temperature of 1741 K. | ||||
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| Notes | Approved | no | |||
| Call Number | Serial | 628 | |||
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| Author | de Lange, Gert; Krieg, Jean-Michel; Honingh, Netty; Karpov, Alexandre; Cherednichenko, Sergey | ||||
| Title | Performance of the HIFI flight mixers | Type | Conference Article | ||
| Year | 2008 | Publication | Proc. 19th Int. Symp. Space Terahertz Technol. | Abbreviated Journal |
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| Volume | Issue | Pages | 98-105 | ||
| Keywords | HEB mixer applications, HEB applications | ||||
| Abstract | We summarize the technology and final results of the superconducting heterodyne SIS and HEB mixers that are developed for the HIFI instrument. Within HIFI 7 frequency bands cover the frequency range from 480 GHz to 1910 GHz. We describe the different device technologies and optical coupling schemes that are used to cover the frequency bands. The efforts of the different mixer teams that participate in HIFI have contributed to an instrument that will have unprecedented sensitivity and frequency coverage. | ||||
| Address | Groningen | ||||
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| Notes | Approved | no | |||
| Call Number | Serial | 1074 | |||
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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 |
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| Volume | 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 |
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| Volume | 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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| Notes | Approved | no | |||
| Call Number | RPLAB @ gujma @ | Serial | 719 | ||
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| Author | Shurakov, Alexander; Tong, Edward; Blundell, Raymond; Gol'tsman, Gregory | ||||
| Title | Microwave stabilization of HEB mixer by a microchip controller | Type | Conference Article | ||
| Year | 2012 | Publication | IEEE MTT-S international microwave symposium digest | Abbreviated Journal |
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| Volume | Issue | Pages | 1-3 | ||
| Keywords | HEB mixer stability, microwave injection, Allan variance, Allan time | ||||
| Abstract | The stability of a Hot Electron Bolometer (HEB) mixer can be improved by the use of microwave injection. In this article we report a refinement of this approach. We introduce a microchip controller to facilitate the implementation of the stabilization scheme, and demonstrate that the feedback loop effectively suppresses drifts in the HEB bias current, leading to an improvement in the receiver stability. The measured Allan time of the mixer's IF output power is increased to > 10 s. | ||||
| Address | Montreal, QC, Canada | ||||
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| Notes | Approved | no | |||
| Call Number | Serial | 857 | |||
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| Author | Khosropanah, P.; Merkel, H.; Yngvesson, S.; Adam, A.; Cherednichenko, S.; Kollberg, E. | ||||
| Title | A distributed device model for phonon-cooled HEB mixers predicting IV characteristics, gain, noise and IF bandwidth | Type | Conference Article | ||
| Year | 2000 | Publication | Proc. 11th Int. Symp. Space Terahertz Technol. | Abbreviated Journal |
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| Volume | Issue | Pages | 474-488 | ||
| Keywords | HEB mixer numerical model, diffusion cooling channel, diffusion channel, distributed HEB model, distributed model | ||||
| Abstract | A distributed model for phonon-cooled superconductor hot electron bolometer (HEB) mixers is given, which is based on solving the one-dimensional heat balance equation for the electron temperature profile along the superconductor strip. In this model it is assumed that the LO power is absorbed uniformly along the bridge but the DC power absorption depends on the local resistivity and is thus not uniform. The electron temperature dependence of the resistivity is assumed to be continuous and has a Fermi form. These assumptions are used in setting up the non-linear heat balance equation, which is solved numerically for the electron temperature profile along the bolometer strip. Based on this profile the resistance of the device and the IV curves are calculated. The IV curves are in excellent agreement with measurement results. Using a small signal model the conversion gain of the mixer is obtained. The expressions for Johnson noise and thermal fluctuation noise are derived. The calculated results are in close agreement with measurements, provided that one of the parameters used is adjusted. | ||||
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| Publisher | Place of Publication | University of Michigan, Ann Arbor, MI USA | Editor | ||
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| Notes | Approved | no | |||
| Call Number | Serial | 893 | |||
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| Author | Ynvesson, K. Sigfrid; Kollberg, Erik L. | ||||
| Title | Optimum receiver noise temperature for NbN HEB mixers according to standard model | Type | Conference Article | ||
| Year | 1999 | Publication | Proc. 10th Int. Symp. Space Terahertz Technol. | Abbreviated Journal |
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| Volume | Issue | Pages | 566-582 | ||
| Keywords | HEB mixer model, standard model, electro-thermal feedback, self-heating parameter, heating efficiency | ||||
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| Notes | Approved | no | |||
| Call Number | Serial | 895 | |||
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| Author | Khosropanah, Pourya | ||||
| Title | NbN and NbTiN hot electron bolometer THz mixers | Type | Book Whole | ||
| Year | 2003 | Publication | Chalmers University of Technology | Abbreviated Journal |
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| Keywords | HEB mixer, hot electron bolometer mixer, NbN, NbTiN, superconducting detector, heterodyne receiver, THz mixer, submillimeter mixer, quasioptical receiver, double slot antenna, twin slot antenna, spiral antenna, receiver noise, FTS, Fourier Transform Spectrometer | ||||
| Abstract | The thesis reports the development of Hot Electron Bolometer (HEB) mixers for radio astronomy heterodyne receivers in THz frequency range. Part of this work is the fabrication of HEB devices, which are based on NbN or NbTiN superconducting thin films (â‰<a4>5 nm). They are integrated with wideband spiral or double-slot planar antennas. The mixer chips are incorporated into a quasi-optical receiver. The experimental part of this work focuses on the characterization of the receiver as a whole, and the HEB mixers as a part. Double side band receiver noise temperature and the IF bandwidth are reported for frequencies from 0.7 THz up to 2.6 THz. The spectrum of the direct response of HEB integrated with dierent antennas are measured using Fourier Transform Spectrometer (FTS). The effect of the bolometer size on total receiver performance and the LO power requirements is also discussed. A high-yield and reliable process for fabrication of NbN HEB mixers have been achieved. Over 100 devices with different bolometer geometry, film property and also different antennas have been fabricated and measured. The measured data enables us to discuss the impact of different parameters to the receiver overall performance. This work has provided NbN HEB mixers to the following receivers: TREND (Terahertz REceiver with NbN HEB Device) operating at 1.25-1.5 THz, installed in AST/RO Submillimeter Wave Telescope, Amundsen/Scott South Pole Station, in 2002-2003. Band 6-low (1.410-1.700 THz) and 6-high (1.700-1.920 THz) of the HIFI (Heterodyne Instrument for Far Infra-red) in the Herschel Space Observatory, due to launch in 2007 by ESA (European Space Agency). Besides, there has been continuous efforts to develop better models to explain the mixer performance more accurately. They are based on two temperature model for electrons and phonons and solving one-dimensional heat balance equations along the bolometer. The principles of these models are illustrated and the calculated results are compared with measured data. |
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| Corporate Author | Thesis | Ph.D. thesis | |||
| Publisher | Chalmers University of Technology | Place of Publication | Göteborg | Editor | |
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| Notes | Approved | no | |||
| Call Number | Serial | 910 | |||
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