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Kardakova, A. (author), Shishkin, A. (author), Semenov, A. (author), Goltsman, G.N. (author), Ryabchun, S. (author), Klapwijk, T.M. (author), Bousquet, J. (author), Eon, D. (author), Sacépé, B. (author), Klein, T. (author), Bustarret, E. (author)We report a study of the relaxation time of the restoration of the resistive superconducting state in single crystalline boron-doped diamond using amplitude-modulated absorption of (sub-)THz radiation (AMAR). The films grown on an insulating diamond substrate have a low carrier density of about 2.5×1021cm?3 and a critical temperature of about 2K...journal article 2016
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Wiedenmann, J. (author), Bocquillon, E. (author), Deacon, R.S. (author), Hartinger, S. (author), Hermann, O. (author), Klapwijk, T.M. (author), Maier, L. (author), Ames, C. (author), Brüne, C. (author), Gould, C. (author), Oiwa, A. (author), Ishibashi, K. (author), Tarucha, S. (author), Buhmann, H. (author), Molenkamp, L.W. (author)The Josephson effect describes the generic appearance of a supercurrent in a weak link between two superconductors. Its exact physical nature deeply influences the properties of the supercurrent. In recent years, considerable efforts have focused on the coupling of superconductors to the surface states of a three-dimensional topological...journal article 2016
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Shcherbatenko, M. (author), Lobanov, Y. (author), Benderov, O. (author), Shurakov, A. (author), Ignatov, A. (author), Titova, N. (author), Finkel, M. (author), Maslennikov, S. (author), Kaurova, N. (author), Voronov, B.M. (author), Rodin, A. (author), Klapwijk, T.M. (author), Gol'tsman, G.N. (author)We report on design and characterization of a superconducting Hot Electron Bolometer Mixer integrated with a logarithmic spiral antenna for mid-IR range observations. The antenna parameters have been adjusted to achieve the ultimate performance at 10 ?m (30 THz) range where O3, NH3, CO2, CH4, N2O, . lines in the Earth’s atmosphere, in planetary...conference paper 2015
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De Visser, P.J. (author), Yates, S.J.C. (author), Guruswamy, T. (author), Goldie, D.J. (author), Withington, S. (author), Neto, A. (author), Llombart, N. (author), Baryshev, A.M. (author), Klapwijk, T.M. (author), Baselmans, J.J.A. (author)We have measured the absorption of terahertz radiation in a BCS superconductor over a broad range of frequencies from 200 GHz to 1.1 THz, using a broadband antenna-lens system and a tantalum microwave resonator. From low frequencies, the response of the resonator rises rapidly to a maximum at the gap edge of the superconductor. From there on,...journal article 2015
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Gaudenzi, R. (author), Island, J.O. (author), De Bruijckere, J. (author), Burzuri, E. (author), Klapwijk, T.M. (author), Van der Zant, H.S.J. (author)We demonstrate that electronic transport through single molecules or molecular ensembles, commonly based on gold (Au) electrodes, can be extended to superconducting electrodes by combining gold with molybdenum-rhenium (MoRe). This combination induces proximity-effect superconductivity in the gold to temperatures of at least 4.6K and magnetic...journal article 2015
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Baryshev, A.M. (author), Hesper, R. (author), Mena, F.P. (author), Klapwijk, T.M. (author), Van Kempen, T.A. (author), Hogerheijde, M.R. (author), Jackson, B.D. (author), Adema, J. (author), Gerlofsma, G.J. (author), Bekema, M.E. (author), Barkhof, J. (author), De Haan-Stijkel, L.H.R. (author), Van den Bemt, M. (author), Koops, A. (author), Keizer, K. (author), Pieters, C. (author), Koops van het Jagt, J. (author), Schaeffer, H.H.A. (author), Zijlstra, T. (author), Kroug, M. (author), Lodewijk, C.F.J. (author), Wielinga, K. (author), Boland, W. (author), Van Dishoeck, E.F. (author), Jager, H. (author), Wild, W. (author)Aims. We describe the design, construction, and characterization of the Band 9 heterodyne receivers (600–720 GHz) for the Atacama Large Millimeter/submillimeter Array (ALMA). First-light Band 9 data, obtained during ALMA commissioning and science verification phases, are presented as well. Methods. The ALMA Band 9 receiver units (so-called ...journal article 2015
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Klapwijk, T.M. (author)The invention provides aterahertz scanning probe microscope setup comprising (i) a terahertz radiation source configured to generate terahertz radiation; (ii) a terahertz lens configured to receive at least part of the terahertz radiation from the terahertz radiation source; (iii) a cantilever unit comprising a cantilever with at its distal end...patent 2014
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De Visser, P.J. (author), Baselmans, J.J.A. (author), Bueno, J. (author), Llombart, N. (author), Klapwijk, T.M. (author)In a superconductor, in which electrons are paired, the density of unpaired electrons should become zero when approaching zero temperature. Therefore, radiation detectors based on breaking of pairs promise supreme sensitivity, which we demonstrate using an aluminium superconducting microwave resonator. Here we show that the resonator also...journal article 2014
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De Visser, P.J. (author), Goldie, D.J. (author), Diener, P. (author), Withington, S. (author), Baselmans, J.J.A. (author), Klapwijk, T.M. (author)In a superconductor, absorption of photons with an energy below the superconducting gap leads to redistribution of quasiparticles over energy and thus induces a strong nonequilibrium quasiparticle energy distribution. We have measured the electrodynamic response, quality factor, and resonant frequency of a superconducting aluminium microwave...journal article 2014
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Kardakova, A. (author), Finkel, M. (author), Morozov, D. (author), Kovalyuk, V. (author), An, P. (author), Dunscombe, C. (author), Tarkhov, M. (author), Mauskopf, P. (author), Klapwijk, T.M. (author), Goltsman, G. (author)We report on the direct measurement of the electron-phonon relaxation time, ?eph, in disordered TiN films. Measured values of ?eph are from 5.5?ns to 88?ns in the 4.2 to 1.7?K temperature range and consistent with a T?3 temperature dependence. The electronic density of states at the Fermi level N0 is estimated from measured material parameters....journal article 2013
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Peltonen, J.T. (author), Astafiev, O.V. (author), Korneeva, Y.P. (author), Voronov, B.M. (author), Korneev, A.A. (author), Charaev, I.M. (author), Semenov, A.V. (author), Golt'sman, G.N. (author), Ioffe, L.B. (author), Klapwijk, T.M. (author), Tsai, J.S. (author)We demonstrate evidence of coherent magnetic flux tunneling through superconducting nanowires patterned in a thin highly disordered NbN film. The phenomenon is revealed as a superposition of flux states in a fully metallic superconducting loop with the nanowire acting as an effective tunnel barrier for the magnetic flux, and reproducibly...journal article 2013
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Janssen, R.M.J. (author), Baselmans, J.J.A. (author), Endo, A. (author), Ferrari, L. (author), Yates, S.J.C. (author), Baryshev, A.M. (author), Klapwijk, T.M. (author)We demonstrate photon noise limited performance in both phase and amplitude readout in microwave kinetic inductance detectors (MKIDs) consisting of NbTiN and Al, down to 100 fW of optical power. We simulate the far field beam pattern of the lens-antenna system used to couple radiation into the MKID and derive an aperture efficiency of 75%. This...journal article 2013
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Coumou, P.C.J.J. (author), Driessen, E.F.C. (author), Bueno, J. (author), Chapelier, C. (author), Klapwijk, T.M. (author)We have studied the electrodynamic response of strongly disordered superconducting TiN films using microwave resonators, where the disordered superconductor is the resonating element in a high-quality superconducting environment of NbTiN. We describe the response assuming an effective pair-breaking mechanism modifying the density of states and...journal article 2013
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Fedorov, G. (author), Kardakova, A. (author), Gayduchenko, I. (author), Charayev, I. (author), Voronov, B.M. (author), Finkel, M. (author), Klapwijk, T.M. (author), Morozov, S. (author), Presniakov, M. (author), Bobrinetskiy, I. (author), Ibragimov, R. (author), Goltsman, G. (author)We report on the voltage response of carbon nanotube devices to sub-terahertz (THz) radiation. The devices contain carbon nanotubes (CNTs), which are over their length partially suspended and partially Van der Waals bonded to a SiO2 substrate, causing a difference in thermal contact. We observe a DC voltage upon exposure to 140?GHz radiation....journal article 2013
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Westig, M.P. (author), Selig, S. (author), Jacobs, K. (author), Klapwijk, T.M. (author), Honingh, C.E. (author)In this paper, we demonstrate experimentally the implementation of a niobium-trilayer junction with an aluminum-oxide tunnel barrier, embedded in a high-gap superconducting niobium-titanium-nitride circuit. Previously reported heating by quasiparticle trapping is removed by inserting a normal metal layer of gold between the niobium junction and...journal article 2013
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Endo, A. (author), Sfiligoj, C. (author), Yates, S.J.C. (author), Baselmans, J.J.A. (author), Thoen, D.J. (author), Javadzadeh, S.M.H. (author), Van der Werf, P.P. (author), Baryshev, A.M. (author), Klapwijk, T.M. (author)We experimentally demonstrate the principle of an on-chip submillimeter wave filter bank spectrometer, using superconducting microresonators as narrow band-separation filters. The filters are made of NbTiN/SiNx/NbTiN microstrip line resonators, which have a resonance frequency in the range of 614-685?GHz, two orders of magnitude higher in...journal article 2013
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Ranjan, V. (author), De Lange, G. (author), Schutjens, R. (author), Debelhoir, T. (author), Groen, J.P. (author), Szombati, D. (author), Thoen, D.J. (author), Klapwijk, T.M. (author), Hanson, R. (author), DiCarlo, L. (author)We study spin relaxation and diffusion in an electron-spin ensemble of nitrogen impurities in diamond at low temperature (0.25–1.2 K) and polarizing magnetic field (80–300 mT). Measurements exploit field-controlled coupling of the ensemble to two modes of a transmission-line resonator. The observed temperature-independent spin relaxation time...journal article 2013
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Kloosterman, J.L. (author), Hayton, D.J. (author), Ren, Y. (author), Kao, T.Y. (author), Hovenier, J.N. (author), Gao, J.R. (author), Klapwijk, T.M. (author), Hu, Q. (author), Walker, C.K. (author), Reno, J.L. (author)We report on a heterodyne receiver designed to observe the astrophysically important neutral atomic oxygen [OI] line at 4.7448?THz. The local oscillator is a third-order distributed feedback quantum cascade laser operating in continuous wave mode at 4.741?THz. A quasi-optical, superconducting NbN hot electron bolometer is used as the mixer. We...journal article 2013
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Driessen, E.F.C. (author), Coumou, P.C.J.J. (author), Tromp, R.R. (author), De Visser, P.J. (author), Klapwijk, T.M. (author)We probe the effects of strong disorder (2.4<kFl<8.6) on superconductivity in thin films of niobium titanium nitride and titanium nitride by measuring the microwave electrodynamics in coplanar waveguide resonators. We find a gradual evolution of the electromagnetic response with disorder, deviating from BCS theory, for both materials. This...journal article 2012
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Ren, Y. (author), Hayton, D.J. (author), Hovenier, J.N. (author), Cui, M. (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 demonstrate an experimental scheme to simultaneously stabilize the frequency and amplitude of a 3.5 THz third-order distributed feedback quantum cascade laser as a local oscillator. The frequency stabilization has been realized using a methanol absorption line, a power detector, and a proportional-integral-derivative (PID) loop. The amplitude...journal article 2012