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Author Irimajiri, Y.; Kumagai, M.; Morohashi, I.; Kawakami, A.; Nagano, S.; Sekine, N.; Ochiai, S.; Tanaka, S.; Hanado, Y.; Uzawa, Y.; Hosako, I. doi  isbn
openurl 
  Title Phase-locking of a THz-QCL using a Low Noise HEB mixer, and a Frequency-comb as a Reference Type Conference Article
  Year 2014 Publication 39th Int. Conf. IRMMW-THz Abbreviated Journal 39th Int. Conf. IRMMW-THz  
  Volume Issue Pages 1-2  
  Keywords  
  Abstract We have developed a phase-locking system of a 3.1THz QCL (Quantum Cascade Laser) using a low noise hot electron bolometer mixer (HEBM) and a THz reference. The THz reference was generated by photomixing two optical modes of a frequency comb. The THz-QCL and HEBM devices are fabricated in our laboratory. A line width of the phase-locked QCL of narrower than 1Hz was achieved.  
  Address  
  Corporate Author (up) 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 978-1-4799-3877-3 Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number RPLAB @ atomics90 @ Serial 969  
Permanent link to this record
 

 
Author Pütz P.; Büchel D.; Jacobs K.; Schultz M.; Honingh C.E.; Stutzki J. openurl 
  Title Waveguide Hot Electron Bolometer Mixer development for upGREAT Type Journal Article
  Year 2014 Publication Kosma Abbreviated Journal  
  Volume Issue Pages  
  Keywords  
  Abstract We report on our hot electron bolometer mixer development for the focal plane array extension upGREAT of the German Receiver for Astronomy at Terahertz frequencies (GREAT) operated on SOFIA. For (up)GREAT we have pushed the waveguide technology to 4.7 THz and present RF performance results. We describe the RF planar circuit design, the micro fabrication employing NbN microbridges on 2 µm thin Si membrane substrates and the machining technology used for the waveguides. One of the 4.7 THz mixers was used in the high frequency channel on GREAT in May 2014 and performed as expected from the laboratory characterization.  
  Address  
  Corporate Author (up) 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 RPLAB @ atomics90 @ Serial 970  
Permanent link to this record
 

 
Author Ozhegov, R. V.; Gorshkov, K. N.; Vachtomin, Y. B.; Smirnov, K. V.; Finkel, M. I.; Goltsman, G. N.; Kiselev, O. S.; Kinev, N. V.; Filippenko, L. V.; Koshelets, V. P. url  doi
openurl 
  Title Terahertz imaging system based on superconducting heterodyne integrated receiver Type Conference Article
  Year 2014 Publication Proc. THz and Security Applications Abbreviated Journal Proc. THz and Security Applications  
  Volume Issue Pages 113-125  
  Keywords SIS mixer, SIR, THz imaging  
  Abstract The development of terahertz imaging instruments for security systems is on the cutting edge of terahertz technology. We are developing a THz imaging system based on a superconducting integrated receiver (SIR). An SIR is a new type of heterodyne receiver based on an SIS mixer integrated with a flux-flow oscillator (FFO) and a harmonic mixer which is used for phase-locking the FFO. Employing an SIR in an imaging system means building an entirely new instrument with many advantages compared to traditional systems.

In this project we propose a prototype THz imaging system using an 1 pixel SIR and 2D scanner. At a local oscillator frequency of 500 GHz the best noise equivalent temperature difference (NETD) of the SIR is 10 mK at an integration time of 1 s and a detection bandwidth of 4 GHz. The scanner consists of two rotating flat mirrors placed in front of the antenna consisting of a spherical primary reflector and an aspherical secondary reflector. The diameter of the primary reflector is 0.3 m. The operating frequency of the imaging system is 600 GHz, the frame rate is 0.1 FPS, the scanning area is 0.5 × 0.5 m2, the image resolution is 50 × 50 pixels, the distance from an object to the scanner was 3 m. We have obtained THz images with a spatial resolution of 8 mm and a NETD of less than 2 K.
 
  Address  
  Corporate Author (up) Thesis  
  Publisher Springer Netherlands Place of Publication Dordrecht Editor Corsi, C.; Sizov, F.  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 978-94-017-8828-1 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1368  
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Author Zhang, W.; Miao, W.; Zhong, J. Q.; Shi, S. C.; Hayton, D. J.; Vercruyssen, N.; Gao, J. R.; Goltsman, G. N. url  doi
openurl 
  Title Temperature dependence of the receiver noise temperature and IF bandwidth of superconducting hot electron bolometer mixers Type Journal Article
  Year 2014 Publication Supercond. Sci. Technol. Abbreviated Journal Supercond. Sci. Technol.  
  Volume 27 Issue 8 Pages 085013 (1 to 5)  
  Keywords NbN HEB mixers  
  Abstract In this paper we study the temperature dependence of the receiver noise temperature and IF noise bandwidth of superconducting hot electron bolometer (HEB) mixers. Three superconducting NbN HEB devices of different transition temperatures (Tc) are measured at 0.85 THz and 1.4 THz at different bath temperatures (Tbath) between 4 K and 9 K. Measurement results demonstrate that the receiver noise temperature of superconducting NbN HEB devices is nearly constant for Tbath/Tc, less than 0.8, which is consistent with the simulation based on a distributed hot-spot model. In addition, the IF noise bandwidth appears independent of Tbath/Tc, indicating the dominance of phonon cooling in the investigated HEB devices.  
  Address  
  Corporate Author (up) Thesis  
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  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0953-2048 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1358  
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Author Gurovich, B. A.; Tarkhov, M. A.; Prikhod'ko, K. E.; Kuleshova, E. A.; Komarov, D. A.; Stolyarov, V. L.; Olshanskii, E. D.; Goncharov, B. V.; Goncharova, D. A.; Kutuzov, L. V.; Domantovskii, A. G. openurl 
  Title Controlled modification of superconducting properties of NbN ultrathin films under composite ion beam irradiation Type Journal Article
  Year 2014 Publication Nanotechnologies in Russia Abbreviated Journal Nanotechnologies in Russia  
  Volume 9 Issue 7 Pages 386-390  
  Keywords superconducting NbN films composite ion beam irradiation protoning  
  Abstract In this work, the results of studying the microstructure and superconducting properties of ultrathin films on the basis of NbN in the initial state and after modification by being subjecting to composite ion beam irradiation with the energy ~1–3) keV are presented. HRTEM analysis showed that the initial films on the sapphire substrate in orientation “c-cut” are characterized by a grain size essentially exceeding the film thickness, while on the other substrates the size of grains corresponds to the thickness of film. Using XPS analysis, it was shown that in the initial films the atomic ratio of Nb and N is 0.51/0.49, respectively, the percentage of oxygen being lower than 5%. For ultrathin films 5 nm in thickness, the critical temperature of transit to superconducting state (T c) is found to be ~3.6 K and the density of critical current is jc ~8MA/cm2. In the work it is experimentally determined that the irradiation of NbN films by composite ion beams leads to the controlled modification of its superconducting properties due to the process of selective substitution of nitrogen atoms on the oxygen atoms.  
  Address  
  Corporate Author (up) 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 1000  
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