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Author (down) Schubert, J.; Semenov, A.; Gol'tsman, G.; Hübers, H.-W.; Schwaab, G.; Voronov, B.; Gershenzon, E.
Title Noise temperature and sensitivity of a NbN hot-electron mixer at frequencies from 0.7 THz to 5.2 THz Type Conference Article
Year 1999 Publication Proc. 10th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 10th Int. Symp. Space Terahertz Technol.
Volume Issue Pages 190-199
Keywords NbN HEB mixers
Abstract We report on noise temperature measurements of a NbN phonon-cooled hot-electron bolometric mixer at different bias regimes. The device was a 3 nm thick bridge with in-plane dimensions of 1.7 x 0.2 gm 2 integrated in a complementary logarithmic spiral antenna. Measurements were performed at frequencies ranging from 0.7 THz up 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). Two bias regimes are possible in order to achieve low noise temperatures. But only one of them yields sensitivity fluctuations close to the theoretical limit.
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Notes Approved no
Call Number Serial 1573
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Author (down) Schroeder, E.; Mauskopf, P.; Pilyavsky, G.; Sinclair, A.; Smith, N.; Bryan, S.; Mani, H.; Morozov, D.; Berggren, K.; Zhu, D.; Smirnov, K.; Vakhtomin, Y.
Title On the measurement of intensity correlations from laboratory and astronomical sources with SPADs and SNSPDs Type Conference Article
Year 2016 Publication Proc. SPIE Abbreviated Journal Proc. SPIE
Volume 9907 Issue Pages 99070P (1 to 13)
Keywords SPAD, NbN SSPD applications, SNSPD
Abstract We describe the performance of detector modules containing silicon single photon avalanche photodiodes (SPADs) and superconducting nanowire single photon detectors (SNSPDs) to be used for intensity interferometry. The SPADs are mounted in fiber-coupled and free-space coupled packages. The SNSPDs are mounted in a small liquid helium cryostat coupled to single mode fiber optic cables which pass through a hermetic feed-through. The detectors are read out with microwave amplifiers and FPGA-based coincidence electronics. We present progress on measurements of intensity correlations from incoherent sources including gas-discharge lamps and stars with these detectors. From the measured laboratory performance of the correlation system, we estimate the sensitivity to intensity correlations from stars using commercial telescopes and larger existing research telescopes.
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Publisher SPIE Place of Publication Editor Malbet, F.; Creech-Eakman, M.J.; Tuthill, P.G.
Language Summary Language Original Title
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ISSN ISBN Medium
Area Expedition Conference Optical and Infrared Interferometry and Imaging V
Notes Approved no
Call Number Serial 1809
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Author (down) Sáysz, Wojciech; Guziewicz, Marek; Bar, Jan; Wegrzecki, Maciej; Grabiec, Piotr; Grodecki, Remigiusz; Wegrzecka, Iwona; Zwiller, Val; Milosnaya, Irina; Voronov, Boris; Gol’tsman, Gregory; Kitaygorsky, Jen; Sobolewski, Roman
Title Superconducting NbN nanostructures for single photon quantum detectors Type Abstract
Year 2008 Publication Proc. 7-th Int. Conf. Ion Implantation and Other Applications of Ions and Electrons Abbreviated Journal Proc. 7-th Int. Conf. Ion Implantation and Other Applications of Ions and Electrons
Volume Issue Pages 160
Keywords SSPD, SNSPD
Abstract Practical quantum systems such as quantum communication (QC) or quantum measurement systems require detectors with high speed, high sensitivity, high quantum efficiency (QE), and short deadtimes along with precise timing characteristics and low dark counts. Superconducting single photon detectors (SSPDs) based on ultrathin meander type NbN nanostripes (operated at T=2-5K) are a new and highly promising type of devices fulfilling above requirements. In this paper we present results of the SSPDs nanostructure technological optimization. The base for our detector is thin-film (4nm) NbN layer deposited on 350- P m-thick sapphire substrate The active element of the detector is a meander- nanostructure made of 4-nm-thick and 100-nm-wide NbN stripe, covering 10 u 10 P m 2 area with the filling factor ~0,5. The NbN superconducting films were deposited on sapphire substrates by DC reactive magnetron sputtering whereas the meander element of the detector was patterned by the direct electron-beam lithography followed by reactive-ion etching. To enhance the SSPD efficiency at Ȝ = 1.55 P m, we have performed an approach to increase the absorption of the detector by integrating it with optical resonant cavity. An optical microcavity optimized for absorption of 1.55 P m photons was designed as an one-mirror resonator consisting of a Ȝ/4 dielectric layer and a metallic mirror. The microcavity was deposited on the top of the NbN SSPD meander. The resonator was formed by the dielectric SiO 2 layer and metal mirror made of gold or palladium. Microcavity layers were deposited using a magnetron sputtering system.
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Series Editor Series Title Abbreviated Series Title
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Area Expedition Conference
Notes Approved no
Call Number Serial 1409
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Author (down) Saveskul, N. A.; Titova, N. A.; Baeva, E. M.; Semenov, A. V.; Lubenchenko, A. V.; Saha, S.; Reddy, H.; Bogdanov, S. I.; Marinero, E. E.; Shalaev, V. M.; Boltasseva, A.; Khrapai, V. S.; Kardakova, A. I.; Goltsman, G. N.
Title Superconductivity behavior in epitaxial TiN films points to surface magnetic disorder Type Journal Article
Year 2019 Publication Phys. Rev. Applied Abbreviated Journal Phys. Rev. Applied
Volume 12 Issue 5 Pages 054001
Keywords epitaxial TiN films
Abstract We analyze the evolution of the normal and superconducting properties of epitaxial TiN films, characterized by high Ioffe-Regel parameter values, as a function of the film thickness. As the film thickness decreases, we observe an increase of the residual resistivity, that becomes dominated by diffusive surface scattering for d≤20nm. At the same time, a substantial thickness-dependent reduction of the superconducting critical temperature is observed compared to the bulk TiN value. In such high-quality material films, this effect can be explained by a weak magnetic disorder residing in the surface layer with a characteristic magnetic defect density of approximately 1012cm−2. Our results suggest that surface magnetic disorder is generally present in oxidized TiN films.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2331-7019 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1166
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Author (down) Saveskul, N. A.; Titova, N. A.; Baeva, E. M.; Semenov, A. V.; Lubenchenko, A. V.; Saha, S.; Reddy, H.; Bogdanov, S. I.; Marinero, E. E.; Shalaev, V. M.; Boltasseva, A.; Khrapai, V. S.; Kardakova, A. I.; Goltsman, G. N.
Title Superconductivity behavior in epitaxial TiN films points at surface magnetic disorder Type Miscellaneous
Year 2019 Publication arXiv Abbreviated Journal arXiv
Volume Issue Pages 1-10
Keywords
Abstract We analyze the evolution of the normal and superconducting electronic properties in epitaxial TiN films, characterized by high Ioffe-Regel parameter values, as a function of the film thickness. As the film thickness decreases, we observe an increase of in the residual resistivity, which becomes dominated by diffusive surface scattering for d≤20nm. At the same time, a substantial thickness-dependent reduction of the superconducting critical temperature is observed compared to the bulk TiN value. In such a high quality material films, this effect can be explained by a weak magnetic disorder residing in the surface layer with a characteristic magnetic defect density of ∼1012cm−2. Our results suggest that surface magnetic disorder is generally present in oxidized TiN films.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1278
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