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Mair, U.; Suttywong, N.; Hübers, H.-W.; Semenov, A. D.; Richter, H.; Wagner, G.; Birk, M. |
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Development of 1.8 THz receiver for the TELIS instrument |
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Conference Article |
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2005 |
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Proc. 16th Int. Symp. Space Terahertz Technol. |
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Göteborg, Sweden |
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RPLAB @ s @ qo_TELIS_1p8_THz |
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364 |
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Schubert, J.; Semenov, A.; Gol'tsman, G.; Hübers, H.-W.; Schwaab, G.; Voronov, B.; Gershenzon, E. |
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Title |
Noise temperature of an NbN hot-electron bolometric mixer at frequencies from 0.7 THz to 5.2 THz |
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Journal Article |
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Year |
1999 |
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Supercond. Sci. Technol. |
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12 |
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11 |
Pages |
748-750 |
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NbN HEB mixers |
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Abstract |
We report on noise temperature measurements of an NbN phonon-cooled hot-electron bolometric mixer in the terahertz frequency range. The devices were 3 nm thick films with in-plane dimensions 1.7 × 0.2 µm2 and 0.9 × 0.2 µm2 integrated in a complementary logarithmic-spiral antenna. Measurements were performed at seven frequencies ranging from 0.7 THz to 5.2 THz. The measured DSB noise temperatures are 1500 K (0.7 THz), 2200 K (1.4 THz), 2600 K (1.6 THz), 2900 K (2.5 THz), 4000 K (3.1 THz), 5600 K (4.3 THz) and 8800 K (5.2 THz). |
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298 |
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Kroug, M.; Cherednichenko, S.; Choumas, M.; Merkel, H.; Kollberg, E.; Hübers, H.-W.; Richter, H.; Loudkov, D.; Voronov, B.; Gol'Tsman, G. |
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Title |
HEB quasi-optical heterodyne receiver for THz frequencies |
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Conference Article |
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2001 |
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Proc. 12th Int. Symp. Space Terahertz Technol. |
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244-252 |
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Keywords |
HEB mixer, NbN, MgO, conversion gain bandwidth, noise temperature |
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San Diego, CA, USA |
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319 |
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Cherednichenko, S.; Drakinskiy, V.; Lecomte, B.; Dauplay, F.; Krieg, J.-M.; Delorme, Y.; Feret, A.; Hübers, H.-W.; Semenov, A.D.; Gol’tsman, G.N. |
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Terahertz heterodyne array based on NbN HEB mixers |
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2008 |
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Proc. 19th Int. Symp. Space Terahertz Technol. |
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43 |
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Keywords |
NbN HEB mixers array |
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A 16 pixel heterodyne receiver for 2.5 THz is been developed based on NbN superconducting hot-electron bolometer (HEB) mixers. The receiver uses a quasioptical RF coupling approach where HEB mixers are integrated into double dipole antennas on 1.5μm thick Si3N4 / SiO2 membranes. Miniature mirrors (one per pixel) and back short for the antenna were used to design the output mixer beam profile. The camera design allows all 16 pixel IF readout in parallel. The gain bandwidth of the HEB mixers on Si3N4 / SiO 2 membranes was found to be about 3 GHz, when an MgO buffer layers is applied on the membrane. We will also present the progress in the camera heterodyne tests. |
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1411 |
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Il'in, K.; Siegel, M.; Semenov, A.; Engel, A.; Hübers, H.-W.; Hollmann, E.; Gol'tsman, G.; Voronov, B. |
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Thickness dependence of superconducting properties of ultrathin Nb and NbN films |
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Conference Article |
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2004 |
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AKF-Frühjahrstagung |
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Nb, NbN films, has potential plagiarism |
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Berlin-Adlershof |
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1503 |
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Hübers, H.-W.; Semenov, A.; Holldack, K.; Schade, U.; Wüstefeld, G.; Gol’tsman, G. |
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Time domain analysis of coherent terahertz synchrotron radiation |
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Journal Article |
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Year |
2005 |
Publication |
Appl. Phys. Lett. |
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Appl. Phys. Lett. |
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87 |
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18 |
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184103 (1 to 3) |
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Keywords |
NbN HEB mixers, applications |
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The time structure of coherent terahertz synchrotron radiation at the electron storage ring of the Berliner Elektronensynchrotron und Speicherring Gesellschaft has been analyzed with a fast superconducting hot-electron bolometer. The emission from a single bunch of electrons was found to last ∼1500ps at frequencies around 0.4THz, which is much longer than the length of an electron bunch in the time domain (∼5ps). It is suggested that this is caused by multiple reflections at the walls of the beam line. The quadratic increase of the power with the number of electrons in the bunch as predicted for coherent synchrotron radiation and the transition from stable to bursting radiation were determined from a single storage ring fill pattern of bunches with different populations. |
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0003-6951 |
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1457 |
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Semenov, A.; Engel, A.; Il'in, K.; Gol'tsman, G.; Siegel, M.; Hübers, H.-W. |
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Title |
Ultimate performance of a superconducting quantum detector |
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Journal Article |
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2003 |
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Eur. Phys. J. Appl. Phys. |
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Eur. Phys. J. Appl. Phys. |
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21 |
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3 |
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171-178 |
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NbN SSPD, SNSPD |
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We analyze the ultimate performance of a superconducting quantum detector in order to meet requirements for applications in near-infrared astronomy and X-ray spectroscopy. The detector exploits a combined detection mechanism, in which avalanche quasiparticle multiplication and the supercurrent jointly produce a voltage response to a single absorbed photon via successive formation of a photon-induced and a current-induced normal hotspot in a narrow superconducting strip. The response time of the detector should increase with the photon energy providing energy resolution. Depending on the superconducting material and operation conditions, the cut-off wavelength for the single-photon detection regime varies from infrared waves to visible light. We simulated the performance of the background-limited infrared direct detector and X-ray photon counter utilizing the above mechanism. Low dark count rate and intrinsic low-frequency cut-off allow for realizing a background limited noise equivalent power of 10−20 W Hz−1/2 for a far-infrared direct detector exposed to 4-K background radiation. At low temperatures, the intrinsic response time of the counter is rather determined by diffusion of nonequilibrium electrons than by the rate of energy transfer to phonons. Therefore, thermal fluctuations do not hamper energy resolution of the X-ray photon counter that should be better than 10−3 for 6-keV photons. Comparison of new data obtained with a Nb based detector and previously reported results on NbN quantum detectors support our estimates of ultimate detector performance. |
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1286-0042 |
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534 |
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Hübers, H.-W.; Semenov, A.; Richter, H.; Birk, M.; Krocka, M.; Mair, U.; Smirnov, K.; Gol’tsman, G.; Voronov, B. |
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Title |
Terahertz Heterodyn Receiver with a hot-electron bolometer mixer |
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Conference Article |
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2002 |
Publication |
Far-IR, Sub-mm & MM Detector Technology Workshop |
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Far-IR, Sub-mm & MM Detector Technology Workshop |
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3-24 |
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NbN HEB mixers |
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During the past decade major advances have been made regarding low noise mixers for terahertz (THz) heterodyne receivers. State of the art hot-electron-bolometer (HEB) mixers have noise temperatures close to the quantum limit and require less than a µW power from the local oscillator (LO). The technology is now at a point where the performance of a practical receiver employing such mixer, rather than the figures of merit of the mixer itself, are of major concern. We have incorporated a phonon-cooled NbN HEB mixer in a 2.5 THz heterodyne receiver and investigated the performance of the receiver. This yields important information for the development of heterodyne receivers such as GREAT (German receiver for astronomy at THz frequencies aboard SOFIA) [1] and TELIS (Terahertz limb sounder), a balloon borne heterodyne receiver for atmospheric research [2]. Both are currently under development at DLR. |
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NASA |
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Wolf, U.; Farhoomand, J.; McCreight, C.R. |
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NASA CP |
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Volume: 211408 |
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1537 |
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Semenov, A.; Hübers, H.-W.; Engel, A.; Gol’tsman, G. |
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Superconducting quantum detector for far infrared astronomy |
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Conference Article |
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2002 |
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Far-IR, Sub-mm & MM Detector Technology Workshop |
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Far-IR, Sub-mm & MM Detector Technology Workshop |
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3-49 |
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SQD |
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We present the concept of the superconducting quantum detector for astronomy. Response to a single absorbed photon appears due to successive formation of a normal spot and phase-slip-centres in a narrow strip carrying sub-critical supercurrent. The detector simultaneously has a moderate energy resolution and a variable cut-off wavelength depending on both the material used and operation conditions. We simulated performance of the background-limited direct detector having the 100-micrometer cut-off wavelength. Low dark count rate will allow to realise 10-21 W Hz-1/2 noise equivalent power at 4 K background radiation. The detection mechanism provides a moderate 1/20 energy resolution at 50-micrometer wavelength. |
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NASA |
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Wolf, J.; Farhoomand, J.; McCreight, C.R. |
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NASA CP |
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Volume: 211408 |
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1538 |
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Hübers, H.-W.; Schubert, J.; Krabbe, A.; Birk, M.; Wagner, G.; Semenov, A.; Gol’tsman, G.; Voronov, B.; Gershenzon, E. |
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Parylene anti-reflection coating of a quasi-optical hot-electron-bolometric mixer at terahertz frequencies |
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Journal Article |
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2001 |
Publication |
Infrared Physics & Technology |
Abbreviated Journal |
Infrared Physics & Technology |
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42 |
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1 |
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41-47 |
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NbN HEB mixers, anti-reflection coating |
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Parylene C was investigated as anti-reflection coating for silicon at terahertz frequencies. Measurements with a Fourier-transform spectrometer show that the transmittance of pure silicon can be improved by about 30% when applying a layer of Parylene C with a quarter wavelength optical thickness. The 10% bandwidth of this coating extends from 1.5 to 3 THz for a center frequency of 2.3–2.5 THz, where the transmittance is constant. Heterodyne measurements demonstrate that the noise temperature of a hot-electron-bolometric mixer can be reduced significantly by coating the silicon lens of the hybrid antenna with a quarter wavelength Parylene C layer. Compared to the same mixer with an uncoated lens the improvement is about 30% at a frequency of 2.5 THz. |
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1350-4495 |
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1548 |
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Schubert, J.; Semenov, A.; Hübers, H.-W.; Gol'tsman, G.; Schwaab, G.; Voronov, B.; Gershenzon, E. |
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Broad-band terahertz NbN hot-electron bolometric mixer |
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Conference Article |
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1999 |
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Inst. Phys. Conf. |
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Inst. Phys. Conf. |
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167 |
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663-666 |
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NbN HEB mixers |
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4th Europ. Conf. on Appl. Superconductivity, Barcelona, Spain, 14-17 September 1999 |
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1578 |
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Semenov, A. D.; Hübers, H.-W.; Schubert, J.; Gol'tsman, G. N.; Elantiev, A. I.; Voronov, B. M.; Gershenzon, E. M. |
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Design and performance of the lattice-cooled hot-electron terahertz mixer |
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Journal Article |
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2000 |
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J. Appl. Phys. |
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J. Appl. Phys. |
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88 |
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11 |
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6758-6767 |
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HEB mixer, charge imbalance, HF current distribution |
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We present the measurements and the theoreticalmodel of the frequency-dependent noise temperature of a superconductor lattice-cooled hot-electron bolometer mixer in the terahertz frequency range. The increase of the noise temperature with frequency is a cumulative effect of the nonuniform distribution of the high-frequency current in the bolometer and the charge imbalance, which occurs at the edges of the normal domain and at the contacts with normal metal. We show that under optimal operation the fluctuation sensitivity of the mixer is determined by thermodynamic fluctuations of the noise power, whereas at small biases there appears additional noise, which is probably due to the flux flow. We propose the prescription of how to minimize the influence of the current distribution on the mixer performance. |
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0021-8979 |
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306 |
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Lusche, R.; Semenov, A.; Ilin, K.; Siegel, M.; Korneeva, Y.; Trifonov, A.; Korneev, A.; Goltsman, G.; Vodolazov, D.; Hübers, H.-W. |
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Effect of the wire width on the intrinsic detection efficiency of superconducting-nanowire single-photon detectors |
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Journal Article |
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2014 |
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J. Appl. Phys. |
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J. Appl. Phys. |
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Volume |
116 |
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4 |
Pages |
043906 (1 to 9) |
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NbN SSPD, SNSPD, TaN |
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A thorough spectral study of the intrinsic single-photon detection efficiency in superconducting TaN and NbN nanowires with different widths has been performed. The experiment shows that the cut-off of the intrinsic detection efficiency at near-infrared wavelengths is most likely controlled by the local suppression of the barrier for vortex nucleation around the absorption site. Beyond the cut-off quasi-particle diffusion in combination with spontaneous, thermally activated vortex crossing explains the detection process. For both materials, the reciprocal cut-off wavelength scales linearly with the wire width where the scaling factor agrees with the hot-spot detection model. |
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0021-8979 |
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1357 |
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Semenov, A. D.; Hübers, H.-W.; Richter, H.; Birk, M.; Krocka, M.; Mair, U.; Smirnov, K.; Gol'tsman, G. N.; Voronov, B. M. |
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2.5 THz heterodyne receiver with NbN hot-electron-bolometer mixer |
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2002 |
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Phys. C: Supercond. |
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Phys. C: Supercond. |
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372-376 |
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448-453 |
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NbN HEB mixers, applications |
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Abstract |
We describe a 2.5 THz heterodyne receiver for applications in astronomy and atmospheric research. The receiver employs a superconducting NbN phonon-cooled hot-electron-bolometer mixer and an optically pumped far-infrared gas laser as local oscillator. 2200 K double sideband mixer noise temperature was measured at 2.5 THz across a 1 GHz intermediate frequency bandwidth centred at 1.5 GHz. The total conversion losses were 17 dB. The mixer response was linear at load temperatures smaller than 400 K. The receiver was tested in the laboratory environment by measuring the methanol line in emission. Observed pressure broadening confirms the true heterodyne detection regime of the mixer. |
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0921-4534 |
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1526 |
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Author |
Sidorova, M.; Semenov, Alexej D.; Hübers, H.-W.; Ilin, K.; Siegel, M.; Charaev, I.; Moshkova, M.; Kaurova, N.; Goltsman, G. N.; Zhang, X.; Schilling, A. |
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Title |
Electron energy relaxation in disordered superconducting NbN films |
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Journal Article |
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Year |
2020 |
Publication |
Phys. Rev. B |
Abbreviated Journal |
Phys. Rev. B |
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102 |
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5 |
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054501 (1 to 15) |
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NbN SSPD, SNSPD, HEB, bandwidth, relaxation time |
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We report on the inelastic-scattering rate of electrons on phonons and relaxation of electron energy studied by means of magnetoconductance, and photoresponse, respectively, in a series of strongly disordered superconducting NbN films. The studied films with thicknesses in the range from 3 to 33 nm are characterized by different Ioffe-Regel parameters but an almost constant product qTl (qT is the wave vector of thermal phonons and l is the elastic mean free path of electrons). In the temperature range 14–30 K, the electron-phonon scattering rates obey temperature dependencies close to the power law 1/τe−ph∼Tn with the exponents n≈3.2–3.8. We found that in this temperature range τe−ph and n of studied films vary weakly with the thickness and square resistance. At 10 K electron-phonon scattering times are in the range 11.9–17.5 ps. The data extracted from magnetoconductance measurements were used to describe the experimental photoresponse with the two-temperature model. For thick films, the photoresponse is reasonably well described without fitting parameters, however, for thinner films, the fit requires a smaller heat capacity of phonons. We attribute this finding to the reduced density of phonon states in thin films at low temperatures. We also show that the estimated Debye temperature in the studied NbN films is noticeably smaller than in bulk material. |
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2469-9950 |
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