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Author Shurakov, A.; Tong, C.-Y. E.; Blundell, R.; Kaurova, N.; Voronov, B.; Gol'tsman, G. url  doi
openurl 
  Title Microwave stabilization of a HEB mixer in a pulse-tube cryocooler Type Journal Article
  Year 2013 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.  
  Volume 23 Issue 3 Pages (down) 1501504-1501504  
  Keywords NbN HEB mixers  
  Abstract We report the results of our study of the stability of an 800 GHz hot electron bolometer (HEB) mixer cooled with a pulse-tube cryocooler. Pulse-tube cryocoolers introduce temperature fluctuations as well as mechanical vibrations at a frequency of ~1 Hz, both of which can cause receiver gain fluctuations at that frequency. In our system, the motor of the cryocooler was separated from the cryostat to minimize mechanical vibrations, leaving thermal effects as the dominant source of the receiver gain fluctuations. We measured root mean square temperature variations of the 4 K stage of ~7 mK. The HEB mixer was pumped by a solid state local oscillator at 810 GHz. The root mean square current fluctuations at the low noise operating point (1.50 mV, 56.5 μA) were ~0.12 μA, and were predominantly due to thermal fluctuations. To stabilize the bias current, microwave radiation was injected to the HEB mixer. The injected power level was set by a proportional-integral-derivative controller, which completely compensates for the bias current oscillations induced by the pulse-tube cryocooler. Significant improvement in the Allan variance of the receiver output power was obtained, and an Allan time of 5 s was measured.  
  Address  
  Corporate Author Thesis  
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  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 1372  
Permanent link to this record
 

 
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 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 (down) 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 Khosropanah, P.; Gao, J. R.; Laauwen, W. M.; Hajenius, M; Klapwijk, T. M. openurl 
  Title Low noise NbN hot electron bolometer mixer at 4.3 THz Type Journal Article
  Year 2007 Publication Appl. Phys. Lett. Abbreviated Journal Appl. Phys. Lett.  
  Volume 91 Issue Pages (down) 221111 (1 to 3)  
  Keywords NbN HEB mixers, NbN, contacts cleaning  
  Abstract We have studied the sensitivity of a superconducting NbN hot electron bolometer mixer integrated with a spiral antenna at 4.3 THz. Using hot/cold blackbody loads and a beam splitter all in vacuum, we measured a double sideband receiver noise temperature of 1300 K at the optimum local oscillator (LO) power of 330 nW, which is about 12 times the quantum noise (hnu/2kB). Our result indicates that there is no sign of degradation of the mixing process at the superterahertz frequencies. Moreover, a measurement method is introduced which allows us for an accurate determination of the sensitivity despite LO power fluctuations.  
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  Corporate Author Thesis  
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  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 584  
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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 Journal Article
  Year 2005 Publication Appl. Phys. Lett. Abbreviated Journal Appl. Phys. Lett.  
  Volume 87 Issue 18 Pages (down) 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  
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  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 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 (down) 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 Thesis  
  Publisher Place of Publication Editor  
  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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