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Author Hübers, H.-W.; Semenov, A.; Holldack, K.; Schade, U.; Wüstefeld, G.; Gol’tsman, G. url  doi
openurl 
  Title Time domain analysis of coherent terahertz synchrotron radiation Type (up) Journal Article
  Year 2005 Publication Appl. Phys. Lett. Abbreviated Journal Appl. Phys. Lett.  
  Volume 87 Issue 18 Pages 184103 (1 to 3)  
  Keywords NbN HEB mixers, applications  
  Abstract 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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  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 0003-6951 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1457  
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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 An investigation of the performance of the superconducting HEB mixer as a function of its RF embedding impedance Type (up) 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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  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 1439677 Serial 1464  
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Author Meledin, D. V.; Marrone, D. P.; Tong, C.-Y. E.; Gibson, H.; Blundell, R.; Paine, S. N.; Papa, D.C.; Smith, M.; Hunter, T. R.; Battat, J.; Voronov, B.; Gol'tsman, G. url  doi
openurl 
  Title A 1-THz superconducting hot-electron-bolometer receiver for astronomical observations Type (up) Journal Article
  Year 2004 Publication IEEE Trans. Microwave Theory Techn. Abbreviated Journal IEEE Trans. Microwave Theory Techn.  
  Volume 52 Issue 10 Pages 2338-2343  
  Keywords NbN HEB mixer, applications  
  Abstract In this paper, we describe a superconducting hot-electron-bolometer mixer receiver developed to operate in atmospheric windows between 800-1300 GHz. The receiver uses a waveguide mixer element made of 3-4-nm-thick NbN film deposited over crystalline quartz. This mixer yields double-sideband receiver noise temperatures of 1000 K at around 1.0 THz, and 1600 K at 1.26 THz, at an IF of 3.0 GHz. The receiver was successfully tested in the laboratory using a gas cell as a spectral line test source. It is now in use on the Smithsonian Astrophysical Observatory terahertz test telescope in northern Chile.  
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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 0018-9480 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1484  
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Author Meledin, D.; Tong, C.-Y. E.; Blundell, R.; Goltsman, G. url  doi
openurl 
  Title Measurement of intermediate frequency bandwidth of hot electron bolometer mixers at terahertz frequency range Type (up) Journal Article
  Year 2003 Publication IEEE Microw. Wireless Compon. Lett. Abbreviated Journal IEEE Microw. Wireless Compon. Lett.  
  Volume 13 Issue 11 Pages 493-495  
  Keywords waveguide NbN HEB mixers  
  Abstract We have developed a new experimental setup for measuring the IF bandwidth of superconducting hot electron bolometer mixers. In our measurement system we use a chopped hot filament as a broadband signal source, and can perform a high-speed IF scan with no loss of accuracy when compared to coherent methods. Using this technique we have measured the 3 dB IF bandwidth of hot electron bolometer mixers, designed for THz frequency operation, and made from 3-4 nm thick NbN film deposited on an MgO buffer layer over crystalline quartz.  
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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 1531-1309 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1509  
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Author Semenov, A. D.; Hübers, H.-W.; Richter, H.; Birk, M.; Krocka, M.; Mair, U.; Smirnov, K.; Gol'tsman, G. N.; Voronov, B. M. url  doi
openurl 
  Title 2.5 THz heterodyne receiver with NbN hot-electron-bolometer mixer Type (up) Journal Article
  Year 2002 Publication Phys. C: Supercond. Abbreviated Journal Phys. C: Supercond.  
  Volume 372-376 Issue Pages 448-453  
  Keywords NbN HEB mixers, applications  
  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.  
  Address  
  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 0921-4534 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1526  
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Author Cherednichenko, S.; Kroug, M.; Merkel, H.; Khosropanah, P.; Adam, A.; Kollberg, E.; Loudkov, D.; Gol'tsman, G.; Voronov, B.; Richter, H.; Huebers, H.-W. url  doi
openurl 
  Title 1.6 THz heterodyne receiver for the far infrared space telescope Type (up) Journal Article
  Year 2002 Publication Phys. C: Supercond. Abbreviated Journal Phys. C: Supercond.  
  Volume 372-376 Issue Pages 427-431  
  Keywords NbN HEB mixers, applications  
  Abstract A low noise heterodyne receiver is being developed for the terahertz range using a phonon-cooled hot-electron bolometric mixer based on 3.5 nm thick superconducting NbN film. In the 1–2 GHz intermediate frequency band the double-sideband receiver noise temperature was 450 K at 0.6 THz, 700 K at 1.6 THz and 1100 K at 2.5 THz. In the 3–8 GHz IF band the lowest receiver noise temperature was 700 K at 0.6 THz, 1500 K at 1.6 THz and 3000 K at 2.5 THz while it increased by a factor of 3 towards 8 GHz.  
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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 0921-4534 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1527  
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Author Kawamura, J.; Tong, C.-Y. E.; Blundell, R.; Papa, D. C.; Hunter, T. R.; Patt, F.; Gol’tsman, G.; Gershenzon, E. url  doi
openurl 
  Title Terahertz-frequency waveguide NbN hot-electron bolometer mixer Type (up) Journal Article
  Year 2001 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.  
  Volume 11 Issue 1 Pages 952-954  
  Keywords NbN HEB mixers  
  Abstract We have developed a low-noise waveguide heterodyne receiver for operation near 1 THz using phonon-cooled NbN hot-electron bolometers. The mixer elements are submicron-sized microbridges of 4 nm-thick NbN film fabricated on a quartz substrate. Operating at a bath temperature of 4.2 K, the double-sideband receiver noise temperature is 760 K at 1.02 THz and 1100 K at 1.26 THz. The local oscillator is provided by solid-state sources, and power measured at the source is less than 1 /spl mu/W. The intermediate frequency bandwidth exceeds 2 GHz. The receiver was used to make the first ground-based heterodyne detection of a celestial spectroscopic line above 1 THz.  
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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 1558-2515 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1546  
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Author Hübers, H.-W.; Schubert, J.; Krabbe, A.; Birk, M.; Wagner, G.; Semenov, A.; Gol’tsman, G.; Voronov, B.; Gershenzon, E. url  doi
openurl 
  Title Parylene anti-reflection coating of a quasi-optical hot-electron-bolometric mixer at terahertz frequencies Type (up) Journal Article
  Year 2001 Publication Infrared Physics & Technology Abbreviated Journal Infrared Physics & Technology  
  Volume 42 Issue 1 Pages 41-47  
  Keywords NbN HEB mixers, anti-reflection coating  
  Abstract 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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  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 1350-4495 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1548  
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Author Yagoubov, P.; Kroug, M.; Merkel, H.; Kollberg, E.; Schubert, J.; Hubers, H.-W.; Schwaab, G.; Gol'tsman, G.; Gershenzon, E. url  doi
openurl 
  Title Heterodyne measurements of a NbN superconducting hot electron mixer at terahertz frequencies Type (up) Journal Article
  Year 1999 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.  
  Volume 9 Issue 2 Pages 3757-3760  
  Keywords NbN HEB mixers  
  Abstract The performance of a NbN based phonon-cooled Hot Electron Bolometric (HEB) quasioptical mixer is investigated in the 0.65-3.12 THz frequency range. The device is made from a 3 nm thick NbN film on high resistivity Si and integrated with a planar spiral antenna on the same substrate. The in-plane dimensions of the bolometer strip are 0.2/spl times/2 /spl mu/m. The best results of the DSB noise temperature at 1.5 GHz IF frequency obtained with one device are: 1300 K at 650 GHz, 4700 K at 2.5 THz and 10000 K at 3.12 THz. The measurements were performed at 4.5 K ambient temperature. The amount of local oscillator (LO) power absorbed in the bolometer is about 100 nW. The mixer is linear to within 1 dB compression up to the signal level 10 dB below that of the LO. The intrinsic single sideband conversion gain measured at 650 GHz is -9 dB, the total conversion gain is -14 dB.  
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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 1051-8223 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1569  
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Author Lindgren, M.; Currie, M.; Zeng, W.-S.; Sobolewski, R.; Cherednichenko, S.; Voronov, B.; Gol'tsman, G. N. url  doi
openurl 
  Title Picosecond response of a superconducting hot-electron NbN photodetector Type (up) Journal Article
  Year 1998 Publication Appl. Supercond. Abbreviated Journal Appl. Supercond.  
  Volume 6 Issue 7-9 Pages 423-428  
  Keywords NbN SSPD, SNSPD  
  Abstract The ps optical response of ultrathin NbN photodetectors has been studied by electro-optic sampling. The detectors were fabricated by patterning ultrathin (3.5 nm thick) NbN films deposited on sapphire by reactive magnetron sputtering into either a 5×10 μm2 microbridge or 25 1 μm wide, 5 μm long strips connected in parallel. Both structures were placed at the center of a 4 mm long coplanar waveguide covered with Ti/Au. The photoresponse was studied at temperatures ranging from 2.15 K to 10 K, with the samples biased in the resistive (switched) state and illuminated with 100 fs wide laser pulses at 395 nm wavelength. At T=2.15 K, we obtained an approximately 100 ps wide transient, which corresponds to a NbN detector response time of 45 ps. The photoresponse can be attributed to the nonequilibrium electron heating effect, where the incident radiation increases the temperature of the electron subsystem, while the phonons act as the heat sink. The high-speed response of NbN devices makes them an excellent choice for an optoelectronic interface for superconducting digital circuits, as well as mixers for the terahertz regime. The multiple-strip detector showed a linear dependence on input optical power and a responsivity =3.9 V/W.  
  Address  
  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 0964-1807 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1584  
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