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Author Loudkov, D.; Tong, C.-Y. E.; Blundell, R.; Kaurova, N.; Grishina, E.; Voronov, B.; Gol’tsman, G. url  doi
openurl 
  Title (up) An investigation of the performance of the superconducting HEB mixer as a function of its RF embedding impedance Type Journal Article
  Year 2005 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.  
  Volume 15 Issue 2 Pages 472-475  
  Keywords waveguide NbN HEB mixers  
  Abstract We have conducted an investigation of the optimal embedding impedance for a waveguide superconducting hot-electron bolometric (HEB) mixer. Three mixer chip designs for 800 GHz, offering nominal embedding resistances of 70 /spl Omega/, 35 /spl Omega/, and 15 /spl Omega/, have been developed. We used both High Frequency Structure Simulator (HFSS) software and scale model impedance measurements in the design process. We subsequently fabricated HEB mixers to these designs using 3-4 nm thick NbN thin film. Receiver noise temperature measurements and Fourier Transform Spectrometer (FTS) scans were performed to determine the optimal combination of embedding impedance and normal-state resistance for a 50 Ohm IF load impedance. A receiver noise temperature of 440 K was measured at a local oscillator frequency 850 GHz for a mixer with normal state resistance of 62 /spl Omega/ incorporated into a circuit offering a nominal embedding impedance of 70 /spl Omega/. We conclude from our data that, for low noise operation, the normal state resistance of the HEB mixer element should be close to the embedding impedance of the mixer mount.  
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  Notes Approved no  
  Call Number 1439677 Serial 1464  
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Author Loudkov, D.; Tong, C.-Y.E.; Blundell, R.; Kaurova, N.; Grishina, E.; Voronov, B.; Gol’tsman, G. url  openurl
  Title (up) An investigation of the performance of the waveguide superconducting HEB mixer at different RF embedding impedances Type Conference Article
  Year 2005 Publication Proc. 16th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 16th Int. Symp. Space Terahertz Technol.  
  Volume Issue Pages 226-229  
  Keywords waveguide NbN HEB mixers  
  Abstract We have conducted an investigation of the performance of superconducting hot-electron bolometric (HEB) mixer at 800 GHz as a function of the embedding impedance of the waveguide embedding circuit. Using a single half-height mixer block, we have developed three different mixer chip configurations, offering nominal embedding resistances of 70, 35, and 15 Ohms. Both the High Frequency Structure Simulator (HFSS) software and scaled model impedance measurements were employed in the design process. Two batches of HEB mixers were fabricated to these designs using 3-4 nm thick NbN thin film. The mixers were characterized through receiver noise temperature measurements and Fourier Transform Spectrometer (FTS) scans. Briefly, a minimum receiver noise temperature of 440 K was measured at a local oscillator frequency 850 GHz for a mixer of normal state resistance 62 Ohms incorporated into a circuit offering a nominal embedding impedance of 70 Ohms. We conclude from our data that, for low noise operation, the normal state resistance of the HEB mixer element should be close to that of the embedding impedance of the mixer mount.  
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  Series Editor Series Title Abbreviated Series Title  
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  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1472  
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Author Shangina, E. L.; Smirnov, K. V.; Morozov, D. V.; Kovalyuk, V. V.; Gol’tsman, G. N.; Verevkin, A. A.; Toropov, A. I. url  doi
openurl 
  Title (up) Concentration dependence of the intermediate frequency bandwidth of submillimeter heterodyne AlGaAs/GaAs nanostructures Type Journal Article
  Year 2010 Publication Bull. Russ. Acad. Sci. Phys. Abbreviated Journal Bull. Russ. Acad. Sci. Phys.  
  Volume 74 Issue 1 Pages 100-102  
  Keywords 2DEG AlGaAs/GaAs heterostructures, THz heterodyne detectors, IF bandwidth  
  Abstract The concentration dependence of the intermediate frequency bandwidth of heterodyne AlGaAs/GaAs detectors with 2D electron gas is measured using submillimeter spectroscopy with high time resolution at T= 4.2 K. The intermediate frequency bandwidth f3dBfalls from 245 to 145 MHz with increasing concentration of 2D electrons n s = (1.6-6.6) × 10[su11] cm-2. The dependence f3dB ≈ n s – 0.04±is observed in the studied concentration range; this dependence is determined by electron scattering by the deformation potential of acoustic phonons and piezoelectric scattering.  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1062-8738 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1217  
Permanent link to this record
 
 
Author Kerman, A. J.; Dauler, E. A.; Yang, J. K. W.; Rosfjord, K. M.; Anant, V.; Berggren, K. K.; Gol’tsman, G. N.; Voronov, B. M. url  doi
openurl 
  Title (up) Constriction-limited detection efficiency of superconducting nanowire single-photon detectors Type Journal Article
  Year 2007 Publication Appl. Phys. Lett. Abbreviated Journal Appl. Phys. Lett.  
  Volume 90 Issue 10 Pages 101110 (1 to 3)  
  Keywords SSPD, SNSPD  
  Abstract We investigate the source of the large variations in the observed detection efficiencies of superconducting nanowire single-photon detectors between many nominally identical devices. Through both electrical and optical measurements, we infer that these variations arise from “constrictions:” highly localized regions of the nanowires where the effective cross-sectional area for superconducting current is reduced. These constrictions limit the bias-current density to well below its critical value over the remainder of the wire, and thus prevent the detection efficiency from reaching the high values that occur in these devices when they are biased near the critical current density.

This work is sponsored by the United States Air Force under Contract No. FA8721-05-C-0002.		  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0003-6951 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1433  
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Author Fiore, A.; Marsili, F.; Bitauld, D.; Gaggero, A.; Leoni, R.; Mattioli, F.; Divochiy, A.; Korneev, A.; Seleznev, V.; Kaurova, N.; Minaeva, O.; Gol’tsman, G. url  doi
openurl 
  Title (up) Counting photons using a nanonetwork of superconducting wires Type Conference Article
  Year 2009 Publication Nano-Net Abbreviated Journal  
  Volume Issue Pages 120-122  
  Keywords SSPD, SNSPD  
  Abstract We show how the parallel connection of photo-sensitive superconducting nanowires can be used to count the number of photons in an optical pulse, down to the single-photon level. Using this principle we demonstrate photon-number resolving detectors with unprecedented sensitivity and speed at telecommunication wavelengths.  
  Address  
  Corporate Author Thesis  
  Publisher Springer Berlin Heidelberg Place of Publication Berlin, Heidelberg Editor Cheng, M.  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 978-3-642-02427-6 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number 10.1007/978-3-642-02427-6_20 Serial 1242  
Permanent link to this record
 
 
Author Murphy, A.; Semenov, A.; Korneev, A.; Korneeva, Y.; Gol’tsman, G.; Bezryadin, A. url  openurl
  Title (up) Dark counts initiated by macroscopic quantum tunneling in NbN superconducting photon detectors Type Miscellaneous
  Year 2014 Publication arXiv Abbreviated Journal  
  Volume Issue Pages  
  Keywords NbN SSPD  
  Abstract We perform measurements of the switching current distributions of three w = 120 nm wide, 4 nm thick NbN superconducting strips which are used for single-photon detectors. These strips are much wider than the diameter the vortex cores, so they are classified as quasi-two-dimensional (quasi-2D). We discover evidence of macroscopic quantum tunneling by observing the saturation of the standard deviation of the switching distributions at temperatures around 2 K. We analyze our results using the Kurkijarvi-Garg model and find that the escape temperature also saturates at low temperatures, confirming that at sufficiently low temperatures, macroscopic quantum tunneling is possible in quasi-2D strips and can contribute to dark counts observed in single photon detectors.  
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  Notes Approved no  
  Call Number murphy2014dark Serial 1356  
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Author Zhang, W.; Li, N.; Jiang, L.; Ren, Y.; Yao, Q.-J.; Lin, Z.-H.; Shi, S.-C.; Voronov, B. M.; Gol’tsman, G. N. url  doi
openurl 
  Title (up) Dependence of noise temperature of quasi-optical superconducting hot-electron bolometer mixers on bath temperature and optical-axis displacement Type Conference Article
  Year 2008 Publication Proc. SPIE Abbreviated Journal Proc. SPIE  
  Volume 6840 Issue Pages 684007 (1 to 8)  
  Keywords NbN HEB mixers, noise temperature, LO power  
  Abstract It is known that the increase of bath temperature results in the decrease of critical current of superconducting hot-electron bolometer (HEB) mixers owing to the depression of superconductivity, thus leading to the degradation of the mixer’s sensitivity. Here we report our study on the effect of bath temperature on the heterodyne mixing performance of quasi-optical superconducting NbN HEB mixers incorporated with a two-arm log-spiral antenna. The correlation between the bath temperature, critical current, LO power requirement and noise temperature is investigated at 0.5 THz. Furthermore, the heterodyne mixing performance of quasi-optical superconducting NbN HEB mixers is examined while there is an optical-axis displacement between the center of the extended hemispherical silicon lens and the superconducting NbN HEB device, which is placed on the back of the lens. Detailed experimental results and analysis are presented.  
  Address  
  Corporate Author Thesis  
  Publisher Spie Place of Publication Editor Zhang, C.; Zhang, X.-C.  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference Terahertz Photonics  
  Notes Approved no  
  Call Number Serial 1415  
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Author Tikhonov, V. V.; Polyakova, O. N.; Gol’tsman, G. N.; Dzardanov, A. L.; Boyarskiy, D. A. url  doi
openurl 
  Title (up) Determination of dielectric properties of ore minerals in the microwave band Type Journal Article
  Year 2008 Publication Radiophys. Quant. Electron. Abbreviated Journal Radiophys. Quant. Electron.  
  Volume 51 Issue 12 Pages 966-974  
  Keywords ore complex permittivity, chalcopyrite, magnetite, sphalerite, labradorite  
  Abstract We consider a method for determining the complex dielectric permittivity of ore and nonmetal minerals in the microwave band of electromagnetic radiation. The results of measuring the reflectivity and transmittivity of chalcopyrite, magnetite, sphalerite, and labradorite samples in the frequency range 77–300 GHz are presented. A method for calculation of the complex dielectric permittivity of minerals on the basis of the obtained experimental data is proposed. The approximation formulas for calculation of the complex dielectric permittivity of the studied minerals are given.  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0033-8443 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1404  
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Author Semenov, A.; Richter, H.; Smirnov, A.; Günther, B.; Hübers, H.-W.; Il’in, K.; Siegel, M.; Gol’tsman, G.; Drakinskiy, V.; Merkel, H.; Karamarkovic, J. url  openurl
  Title (up) Development of HEB mixers for GREAT and for security screening Type Abstract
  Year 2007 Publication Proc. 18th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 18th Int. Symp. Space Terahertz Technol.  
  Volume Issue Pages 184  
  Keywords NbN HEB mixers, GREAT  
  Abstract We report the study on the quasioptical coupling efficiency and the gain bandwidth of NbN hot-electron bolometer mixers developed for the 4.7 THz channel of the German receiver for Astronomy at THz-frequencies (GREAT) and for security screening at subterahertz frequencies. Radiation coupling efficiency and directive properties of integrated lens antennas with log-spiral, log-periodic and double-slot planar feeds coupled to a hot-electron bolometer were experimentally studied at frequencies from 1 THz to 6 THz and compared with simulations based on the method of moments and the physical-optics ray tracing. For all studied antennas the modeled spectral dependence of the coupling efficiency fits to the experimental data obtained with both Fourier transform spectroscopy and noise temperature measurements only if the complex impedance of the bolometer is explicitly taken into account. Our experimental data did not indicate any noticeable contribution of the quantum noise to the system noise temperature. The experimentally observed deviation of the beam pattern from the model prediction increases with frequency and is most likely due to a non- ideality of the presently used lenses. Study of the intermediate frequency mixer gain at local oscillator (LO) frequencies between 2.5 THz and 0.3 THz showed an increase of the gain bandwidth at low LO frequencies that was understood as the contribution of the direct interaction of magnetic vortices with the radiation field. We have found that the non- homogeneous hot-spot model more adequately describes variation of the intermediate frequency bandwidth with the applied local oscillator power than any of uniform mixer models. The state-of-the-day performance of the GREAT 4.7-THz channel and the 0.8-THz security scanner will be presented.  
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  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1420  
Permanent link to this record
 
 
Author Polyakova, O. N.; Tikhonov, V. V.; Dzardanov, A. L.; Boyarskii, D. A.; Gol’tsman, G. N. url  doi
openurl 
  Title (up) Dielectric characteristics of ore minerals in a 10–40 GHz frequency range Type Journal Article
  Year 2008 Publication Tech. Phys. Lett. Abbreviated Journal Tech. Phys. Lett.  
  Volume 34 Issue 11 Pages 967-970  
  Keywords ore minerals, complex permittivity, sphalerite, magnetite, labradorite  
  Abstract A new approach to investigation of the complex dielectric permittivity of both nonmetallic and ore minerals in the microwave frequency range is proposed. Using this approach, data on the complex permittivity of sphalerite, magnetite, and labradorite in a 10–40 GHz frequency range have been obtained for the first time. A method is proposed for calculating the complex permittivity from experimentally measured frequency dependences of the reflection and transmission coefficients of a plane-parallel plate of a given mineral. Approximate expressions that can be used for calculations of the complex refractive index and permittivity of minerals are presented.  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1063-7850 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1406  
Permanent link to this record
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