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Audley, M.D. (author), De Lange, G. (author), Ferrari, L. (author), Gao, J.R. (author), Hijmering, R.A. (author), Khosropanah, P. (author), Lindeman, M. (author), Ridder, M.L. (author)We have constructed a test facility for characterizing the focal plane arrays of SAFARI, the far-infrared imaging spectrometer for the SPICA satellite. SAFARI’s three bolometer arrays are populated with extremely sensitive (NEP ? 2 × 10?19 W/? Hz) transition edge sensors with a transition temperature close to 100 mK. The extreme sensitivity and...journal article 2012
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Gao, M. (author), Roelvink, J.A. (author)It is estimated that the waterway in North Passage would not be able to meet the demand of shipping development soon and it is necessary to open a new deep navigation channel with a depth of 10 m in North Channel in the near future. A pilot study on the regulation of North Channel was proposed by Yangtze Estuary Waterway Administration Bureau...conference paper 2011
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Ren, Y. (author), Hovenier, J.N. (author), Higgins, R. (author), Gao, J.R. (author), Klapwijk, T.M. (author), Shi, S.C. (author), Klein, B. (author), Kao, T.Y. (author), Hu, Q. (author), Reno, J.L. (author)A frequency tunable terahertz heterodyne spectrometer, based on a third-order distributed feedback quantum cascade laser as a local oscillator, has been demonstrated by measuring molecular spectral lines of methanol (CH3OH) gas at 3.5 THz. By varying the bias voltage of the laser, we achieved a tuning range of ? 1?GHz of the lasing frequency,...journal article 2011
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- Gao, Z. (author) journal article 2011
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- Gao, Q (author), Vassalos, D. (author) report 2011
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- Gao, Lingfeng (author), Ghaemi, Reza (author), Sun, Jing (author) conference paper 2011
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Ren, Y. (author), Gao, J.R. (author), Hovenier, J.N.Higgins, R. (author), Zhang, W. (author), Bell, A. (author), Klein, B. (author), Klapwijk, T.M. (author)High-resolution heterodyne spectrometers operating at above 2 THz are crucial for detecting, e.g., the HD line at 2.7 THz and oxygen OI line at 4.7 THz in astronomy. The potential receiver technology is a combination of a hot electron bolometer (HEB) mixer and a THz quantum cascade laser (QCL) local oscillator (LO).Here we report the first...conference paper 2010
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Walker, C. (author), Kulesa, C. (author), Gao, J.R. (author)In the wavelength regime between 60 and 300 microns there are a number of atomic and molecular emission lines that are key diagnostic probes of the interstellar medium. These include transitions of [CII], [NII], [OI], HD, H2D+, OH, CO, and H2O, some of which are among the brightest global and local far-infrared lines in the Galaxy. In Giant...journal article 2010
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Zhang, W. (author), Gao, J.R. (author), Khosropanah, P. (author), Bansal, T. (author), Klapwijk, T.M. (author), Miao, W. (author), Shi, S.C. (author)We report the sensitivity of a superconducting NbN hot electron bolometer mixer integrated with a tight spiral antenna at 5.3 THz. Using a measurement setup with black body calibration sources and a beam splitter in vacuo, and an antireflection coated Si lens, we obtained a double sideband receiver noise temperature of 1150 K, which is 4.5 times...conference paper 2010
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- Khosropanah, P. (author), Dirks, B. (author), Parra-Borderias, M. (author), Ridder, M. (author), Hijmering, R. (author), Van der Kuur, J. (author), Gottardi, L. (author), Bruijn, M. (author), Popescu, M. (author), Gao, J.R. (author), Hoevers, H. (author) conference paper 2010
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Zhang, W. (author), Khosropanah, P. (author), Gao, J.R. (author), Bansal, T. (author), Klapwijk, T.M. (author), Miao, W. (author), Shi, S.C. (author)We report the measured sensitivities of a superconducting NbN hot electron bolometer (HEB) heterodyne receiver at 5.25 THz. Terahertz (THz) radiation is quasioptically coupled to a HEB mixer with a lens and a spiral antenna. Using a measurement setup with black body calibration sources and a beam splitter in vacuo, and an antireflection coated...journal article 2010
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Hou, D. (author), Han, B. (author), Chen, W. (author), Liang, H. (author), Su, Q. (author), Dorenbos, P. (author), Huang, Y. (author), Gao, Z. (author), Tao, Y. (author)A series of Ce3+ doped ?-Sr2?2xCexNaxP2O7 phosphor compounds has been prepared using a high-temperature solid-state reaction technique. The luminescence properties under vacuum ultraviolet-UV and x-ray excitation were studied. Luminescence spectra reveal three UV-emitting peaks at about 310, 330, and 350 nm from which we conclude that Ce3+...journal article 2010
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Ren, Y. (author), Hovenier, J.N. (author), Higgins, R. (author), Gao, J.R. (author), Klapwijk, T.M. (author), Shi, S.C. (author), Bell, A. (author), Klein, B. (author), Williams, B.S. (author), Kumar, S. (author), Hu, Q. (author), Reno, J.L. (author)A terahertz (THz) heterodyne spectrometer is demonstrated based on a quantum cascade laser (QCL) as a local oscillator (LO) and an NbN hot electron bolometer as a mixer, and it is used to measure high-resolution molecular spectral lines of methanol (CH3OH) between 2.913–2.918 THz. The spectral lines are taken from a gas cell containing methanol...journal article 2010
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Zhang, W. (author), Khosropanah, P. (author), Gao, J.R. (author), Kollberg, E.L. (author), Yngvesson, K.S. (author), Bansal, T. (author), Barends, R. (author), Klapwijk, T.M. (author)We have measured the noise temperature of a single, sensitive superconducting NbN hot electron bolometer (HEB) mixer in a frequency range from 1.6 to 5.3 THz, using a setup with all the key components in vacuum. By analyzing the measured receiver noise temperature using a quantum noise (QN) model for HEB mixers, we confirm the effect of QN. The...journal article 2010
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- Gao, Z. (author) journal article 2010
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Barends, R. (author), Van Vliet, S. (author), Baselmans, J.J.A. (author), Yates, S.J.C. (author), Gao, J.R. (author), Klapwijk, T.M. (author)We present measurements of the quasiparticle relaxation time in Ta superconducting films shaped as planar resonators using the response of the complex conductivity to photon flux. These films have been implanted with magnetic (Mn) as well as non-magnetic atoms (Al). We find a significant decrease of the relaxation time with increasing impurity...conference paper 2009
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Gao, B. (author), Osorio, E.A. (author), Babaei Gaven, K. (author), Van der Zant, H.S.J. (author)We have fabricated nanometer-spaced electrodes on electron-transparent silicon nitride membranes. A thin Cr/Au layer is evaporated on the backside of the membrane which serves as a gate electrode. Using these devices, we have performed three-terminal electron transport measurements on gold nano-particles at liquid helium temperature. Coulomb...journal article 2009
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Khosropanah, P. (author), Baryshev, A. (author), Zhang, W. (author), Jellema, W. (author), Hovenier, J.N. (author), Gao, J.R. (author), Klapwijk, T.M. (author), Paveliev, D.G. (author), Williams, B.S. (author), Kumar, S. (author), Hu, Q. (author), Reno, J.L. (author), Klein, B. (author), Hesler, J.L. (author)We demonstrate the phase locking of a 2.7 THz metal–metal waveguide quantum cascade laser (QCL) to an external microwave signal. The reference is the 15th harmonic, generated by a semiconductor superlattice nonlinear device, of a signal at 182 GHz, which itself is generated by a multiplier chain (x12) from a microwave synthesizer at ~15 GHz....journal article 2009
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Verhagen, S. (author), Retscher, G. (author), Santos, M.C. (author), Ding, X.L. (author), Gao, Y. (author), Jin, S.G. (author)GNSS, InSAR and LIDAR are identified as important techniques when it comes to monitoring and remote sensing of our planet Earth and its atmosphere. In fact, these techniques can be considered as key elements of the Global Geodetic Observing System. Examples of applications are: environmental monitoring; volcano monitoring, land slides, tectonic...conference paper 2009
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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 present measurements of the frequency noise and resonance frequency temperature dependence in planar superconducting resonators on both silicon and sapphire substrates. We show, by covering the resonators with sputtered SiOx layers of different thicknesses, that the temperature dependence of the resonance frequency scales linearly with...journal article 2009