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Ren, Y. (author), Hovenier, J.N. (author), Cui, M. (author), Hayton, D.J. (author), Gao, J.R. (author), Klapwijk, T.M. (author), Shi, S.C. (author), Kao, T.Y. (author), Hu, Q. (author), Reno, J.L. (author)
We report frequency locking of two 3.5-THz third-order distributed feedback (DFB) quantum cascade lasers (QCLs) by using methanol molecular absorption lines, a proportional-integral-derivative controller, and a NbN bolometer. We show that the free-running linewidths of the QCLs are dependent on the electrical and temperature tuning coefficients....
journal article 2012
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Khosropanah, P. (author), Hijmering, R.A. (author), Ridder, M. (author), Lindeman, M.A. (author), Gottardi, L. (author), Bruijn, M. (author), Van der Kuur, J. (author), de Korte, P.A.J. (author), Gao, J.R. (author), Hoevers, H. (author)
Transition edge sensors (TES) are the chosen detector technology for the SAFARI imaging spectrometer on the SPICA telescope. The TES are required to have an NEP of 2–3 × 10?19 W/? Hz to take full advantage of the cooled mirror. SRON has developed TiAu TES bolometers for the short wavelength band (30–60 ?m). The TES are on SiN membranes, in which...
journal article 2012
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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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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, Y. (author), Suchand Sandeep, C.S. (author), Schins, J.M. (author), Houtepen, A.J. (author), Siebbeles, L.D.A. (author)
Auger recombination (AR) can be an important loss mechanism for optoelectronic devices, but it is typically not very efficient at low excitation densities. Here we show that in conductive quantum-dot solids, AR is the dominant charge carrier decay path even at excitation densities as low as 10?3 per quantum dot, and that AR becomes faster as the...
journal article 2013
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Gao, Z. (author)
journal article 2009
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Wilms Fleet, D. (author), Gao, J.R. (author), Klapwijk, T.M. (author), de Eorte, P.A.J. (author)
journal article 2001
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Gao, H. (author), Hrachowitz, M. (author), Schymanski, S. (author), Fenicia, F.F. (author), Sriwongsitanon, N. (author), Savenije, H.H.G. (author)
journal article 2015
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Mei, X. (author), Dai, Z. (author), Van Gelder, P.H.A.J.M. (author), Gao, J. (author)
The magnitude of anthropogenic influence, especially dam regulation, on hydrological system is of scientific and practical value for large river management. As the largest dam in the world by far, Three Gorges Dam (TGD) is expected to be a strong evidence on dam impacts on downstream hydrological regime. In this study, statistical methods are...
journal article 2015
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Adam, A.J.L. (author), Kašalynas, I. (author), Hovenier, J.N. (author), Klaassen, T.O. (author), Gao, J.R. (author), Orlova, E.E. (author), Williams, B.S. (author), Kumar, S. (author), Hu, Q. (author), Reno, J.L. (author)
The need to reach single-mode lasing and minimize at the same time the electrical dissipation of cryogenically operated terahertz quantum cascade lasers may result in small and subwavelength cavity dimensions. To assess the influence of such dimensions on the shape of the laser emission, we have measured the beam pattern of two metal-metal...
journal article 2006
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Hijmering, R.A. (author), Khosropanah, P. (author), Ridder, M. (author), Lindeman, M. (author), Gottardi, L. (author), Bruijn, M. (author), Van der Kuur, J. (author), De Korte, P. (author), Gao, J.R. (author), Hoervers, H. (author), Jackson, B. (author)
At the Netherlands Institute for Space Research (SRON) we are developing Transition Edge Sensors (TES) bolometers for the SAFARI Imaging Spectrometer on the SPICA telescope. With the current design of the SPICA telescope a background magnetic field of about a Gauss with fluctuations of a couple percent is expected. The effect of this external...
journal article 2012
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Gao, H. (author), Hrachowitz, M. (author), Fenicia, F.F. (author), Gharari, S. (author), Savenije, H.H.G. (author)
Although elevation data are globally available and used in many existing hydrological models, their information content is still underexploited. Topography is closely related to geology, soil, climate and land cover. As a result, it may reflect the dominant hydrological processes in a catchment. In this study, we evaluated this hypothesis...
journal article 2014
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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), 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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Gao, J.R. (author), de Graaf, C. (author), Schüssler, A.S. (author), Caro, J. (author), Radelaar, S. (author), Heyers, K. (author)
journal article 1992
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Durucan, S. (author), Korre, A. (author), Shi, J.Q. (author), Idiens, M. (author), Stanczyk, K. (author), Kapusta, K. (author), Rogut-Dabrowska, A. (author), Kempka, T. (author), Wolf, K.H.A.A. (author), Younger, P. (author), Zavsek, S. (author), Poulsen, N.E. (author), Bojda, D. (author), Franzsen, S. (author), Muresan, M. (author), Gao, J. (author), Beath, A. (author), Mastalerz, M. (author)
The TOPS project takes a radical and holistic approach to coupled UCG-CCS, and thus the site selection criteria for the coupled processes, considering both geological, reservoir and process engineering aspects and different end-uses of the produced synthetic gas in order to optimise the whole value chain. In particular, the experimental research...
journal article 2014
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Barends, R. (author), Hajenius, M. (author), Gao, J.R. (author), Klapwijk, T.M. (author)
We present a description of the current-voltage characteristics of hot electron bolometers in terms of the current-dependent intrinsic resistive transition of NbN films. We find that, by including this current dependence, we can correctly predict the complete current-voltage characteristics, showing excellent agreement with measurements for both...
journal article 2005
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Gao, Junliang (author), Ma, Xiaozhou (author), Dong, Guohai (author), Wang, Gang (author), Ma, Yuxiang (author)
journal article 2014
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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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