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Barends, R. (author), Hortensius, H.L. (author), Zijlstra, T. (author), Baselmans, J.J.A. (author), Yates, S.J.C. (author), Gao, J.R. (author), Klapwijk, T.M. (author)
We study NbTiN resonators by measurements of the temperature dependent resonance frequency and frequency noise. Additionally, resonators are studied covered with SiOx dielectric layers of various thicknesses. The resonance frequency develops a nonmonotonic temperature dependence with increasing SiOx layer thickness. The increase in the noise is...
journal article 2008
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Hajenius, M. (author), Khosropanah, P. (author), Hovenier, J.N. (author), Gao, J.R. (author), Klapwijk, T.M. (author), Barbieri, S. (author), Dhillon, S. (author), Filloux, P. (author), Sirtori, C. (author), Ritchie, D.A. (author), Beere, H.E. (author)
We characterize a heterodyne receiver based on a surface-plasmon waveguide quantum cascade laser (QCL) emitting at 2.84 THz as a local oscillator, and an NbN hot electron bolometer as a mixer. We find that the envelope of the far-field pattern of the QCL is diffraction-limited and superimposed onto interference fringes, which are similar to...
journal article 2008
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Kalmanovitz, N.R. (author), Hoxha, I. (author), Jin, Y. (author), Vitkalov, S.A. (author), Sarachik, M.P. (author), Larkin, I.A. (author), Klapwijk, T.M. (author)
journal article 2008
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Mena, F.P. (author), Kooi, J.W. (author), Baryshev, A.M. (author), Lodewijk, C.F.J. (author), Hesper, R. (author), Wild, W. (author), Klapwijk, T.M. (author)
journal article 2008
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Zijlstra, T. (author), Lodewijk, C.F.J. (author), Vercruyssen, N. (author), Tichelaar, F.D. (author), Loudkov, D.N. (author), Klapwijk, T.M. (author)
High critical current-density (10?to?420?kA/cm2) superconductor-insulator-superconductor tunnel junctions with aluminum nitride barriers have been realized using a remote nitrogen plasma from an inductively coupled plasma source operated in a pressure range of 10?3–10?1?mbar. We find a much better reproducibility and control compared to previous...
journal article 2007
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Khosropanah, P. (author), Gao, J.R. (author), Laauwen, W.M. (author), Hajenius, M. (author), Klapwijk, T.M. (author)
We have studied the sensitivity of a superconducting NbN hot electron bolometer mixer integrated with a spiral antenna at 4.3?THz. Using hot/cold blackbody loads and a beam splitter all in vacuum, we measured a double sideband receiver noise temperature of 1300?K at the optimum local oscillator (LO) power of 330?nW, which is about 12 times the...
journal article 2007
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Khosropanah, P. (author), Laauwen, W.M. (author), Gao, J.R. (author), Hajenius, M. (author), Hovenier, J.N. (author), Klapwijk, T.M. (author)
We have characterized a heterodyne receiver based on an NbN hot electron bolometer integrated with spiral antenna as mixer and an optically pumped FIR ring laser at 4.3 THz as local oscillator (LO). We succeeded in measuring the receiver output power, responding to the hot/cold load, as a function of bias voltage at optimum LO power. From the...
conference paper 2007
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Gao, J.R. (author), Hajenius, M. (author), Tichelaar, F.D. (author), Klapwijk, T.M. (author), Voronov, B. (author), Grishin, E. (author), Gol'tsman, G. (author), Zorman, C.A. (author), Mehregany, M. (author)
The authors have realized NbN (100) nanofilms on a 3C-SiC (100)/Si(100) substrate by dc reactive magnetron sputtering at 800?°C. High-resolution transmission electron microscopy (HRTEM) is used to characterize the films, showing a monocrystalline structure and confirming epitaxial growth on the 3C-SiC layer. A film ranging in thickness from 3.4...
journal article 2007
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Goennenwein, S.T.B. (author), Schink, S.W. (author), Brandlmaier, A. (author), Boger, A. (author), Opel, M. (author), Gross, R. (author), Keizer, R.S. (author), Klapwijk, T.M. (author), Gupta, A. (author), Huebl, H. (author), Bihler, C. (author), Brandt, M.S. (author)
We study the magnetoresistance properties of thin ferromagnetic CrO2 and Fe3O4 films under microwave irradiation. Both the sheet resistance ? and the Hall voltage VHall characteristically change when a ferromagnetic resonance (FMR) occurs in the film. The electrically detected ferromagnetic resonance (EDFMR) signals closely match the...
journal article 2007
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Goennenwein, S.T.B. (author), Keizer, R.S. (author), Schink, S.W. (author), Van Dijk, I. (author), Klapwijk, T.M. (author), Miao, G.X. (author), Xiao, G. (author), Gupta, A. (author)
We have measured the in-plane anisotropic magnetoresistance of 100?nm thick CrO2 thin films at liquid He temperatures. In low magnetic fields H, both the longitudinal and the transverse (planar Hall) resistance show abrupt switches, which characteristically depend on the orientation of H. All the experimental findings consistently demonstrate...
journal article 2007
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Kooi, J.W. (author), Baselmans, J.J.A. (author), Hajenius, M. (author), Gao, J.R. (author), Klapwijk, T.M. (author), Dieleman, P. (author), Baryshev, A. (author), De Lange, G. (author)
The intermediate frequency (IF) characteristics, the frequency dependent IF impedance, and the mixer conversion gain of a small area hot electron bolometer (HEB) have been measured and modeled. The device used is a twin slot antenna coupled NbN HEB mixer with a bridge area of 1×0.15??m2, and a critical temperature of 8.3?K. In the experiment the...
journal article 2007
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Russo, S. (author), Klapwijk, T.M. (author), Schoch, W. (author), Limmer, W. (author)
journal article 2007
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Russo, S. (author), Tobiska, J. (author), Klapwijk, T.M. (author), Morpurgo, A.F. (author)
journal article 2007
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Baselmans, J.J.A. (author), Baryshev, A. (author), Reker, S.F. (author), Hajenius, M. (author), Gao, J.R. (author), Klapwijk, T.M. (author), Voronov, B. (author), Gol'tsman, G. (author)
We present a detailed experimental study of the direct detection effect in a small volume (0.15??m×1??m×3.5?nm) quasioptical NbN phonon cooled hot electron bolometer mixer at 673?GHz. We find that the small signal noise temperature, relevant for an astronomical observation, is 20% lower than the noise temperature obtained using 300 and 77?K...
journal article 2006
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Hajenius, M. (author), Baselmans, J.J.A. (author), Baryshev, A. (author), Gao, J.R. (author), Klapwijk, T.M. (author), Kooi, J.W. (author), Jellema, W. (author), Yang, Z.Q. (author)
We present a complete experimental characterization of a quasioptical twin-slot antenna coupled small area (1.0×0.15??m2) NbN hot electron bolometer (HEB) mixer compatible with currently available solid state tunable local oscillator (LO) sources. The required LO power absorbed in the HEB is analyzed in detail and equals only 25?nW. Due to the...
journal article 2006
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Kooi, J.W. (author), Baselmans, J.J.A. (author), Baryshev, A. (author), Schieder, R. (author), Hajenius, M. (author), Gao, J.R. (author), Klapwijk, T.M. (author), Voronov, B. (author), Gol'tsman, G. (author)
In this paper we discuss the stability of heterodyne terahertz receivers based on small volume NbN phonon cooled hot electron bolometers (HEBs). The stability of these receivers can be broken down in two parts: the intrinsic stability of the HEB mixer and the stability of the local oscillator (LO) signal injection scheme. Measurements show that...
journal article 2006
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Kasemann, C. (author), Güsten, R. (author), Heyminck, S. (author), Klein, B. (author), Klein, T. (author), Philipp, S.D. (author), Korn, A. (author), Schneider, G. (author), Henseler, A. (author), Baryshev, A. (author), Klapwijk, T.M. (author)
CHAMP+, a dual-color 2 × 7 element heterodyne array for operation in the 450 ?m and 350 ?m atmospheric windows is under development. The instrument, which is currently undergoing final evaluation in the laboratories, will be deployed for commissioning at the APEX telescope in August this year. With its state-of-the-art SIS detectors and wide...
conference paper 2006
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De Lange, G. (author), Jackson, B.D. (author), Jochemsen, M. (author), Laauwen, W.M. (author), De Jong, L. (author), Kroug, M. (author), Zijlstra, T. (author), Klapwijk, T.M. (author)
We describe the performance of the Band 3 and Band 4 Flight Model mixer units for Herschel/HIFI Instrument. These units are part of the Focal Plane Unit of HIFI. The band 3 and 4 mixer units cover the 800-960 GHz and 960-1120 GHz frequency range and have a 4-8 GHz IF frequency band. The sensitivities of the mixers within the HIFI setting are...
conference paper 2006
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Keizer, R.S. (author), Flokstra, M.G. (author), Aarts, J. (author), Klapwijk, T.M. (author)
journal article 2006
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Shashkin, A.A. (author), Anissimova, S. (author), Sakr, M.R. (author), Kravchenko, S.V. (author), Dolgopolov, V.T. (author), Klapwijk, T.M. (author)
journal article 2006
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