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Author Hübers, Heinz-Wilhelm; Semenov, Alexei; Schubert, Josef; Gol'tsman, Gregory; Voronov, Boris; Gershenzon, Evgeni url  openurl
  Title (down) Performance of the phonon-cooled hot-electron bolometric mixer between 0.7 THz and 5.2 THz Type Conference Article
  Year 2000 Publication Proc. 8-th Int. Conf. on Terahertz Electronics Abbreviated Journal Proc. 8-th Int. Conf. on Terahertz Electronics  
  Volume Issue Pages 117-119  
  Keywords NbN HEB mixers  
  Abstract We report on the phonon cooled NbN hot electron bolometer as mixer in the terahertz frequency range. Its hybrid antenna consists of a hyperhemispheric silicon lens and a logarithmic-spiral feed antenna. Noise temperatures have been measured between 0.7 THz and 5.2 THz. A quarter wavelength layer of Parylene works as antireflection coating for the silicon lens and reduces the noise temperature by about 30. It was found that the antenna pattern at 2.5 THz is determined by the feed antenna and not by the diameter of the lens.  
  Address Darmstadt, Germany  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
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  ISSN ISBN Medium  
  Area Expedition Conference International Conference on Terahertz Electronics [8th], Held inDarmstadt, Germany on 28-29 September 2000  
  Notes Approved no  
  Call Number Serial 1553  
Permanent link to this record
 

 
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 (down) Performance of NbN phonon-cooled hot-electron bolometric mixer at Terahertz frequencies Type Conference Article
  Year 1998 Publication Proc. 6-th Int. Conf. Terahertz Electron. Abbreviated Journal Proc. 6-th Int. Conf. Terahertz Electron.  
  Volume Issue Pages 149-152  
  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 results of the DSB noire temperature are: 1300 K at 650 GHz, 4700 K at 2.5 TBz and 10000 K at 3.12 THz. The RF bandwidth of the receiver is at least 2.5 THz. The amount of 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 is measured to be -9 dB, the total conversion gain -14 dB.  
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  Area Expedition Conference IEEE Sixth International Conference on Terahertz Electronics Proceedings. THZ 98. (Cat. No.98EX171)  
  Notes Approved no  
  Call Number Serial 1582  
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Author Kawamura, J.; Blundell, R.; Tong, C.‐yu E.; Gol’tsman, G.; Gershenzon, E.; Voronov, B. url  doi
openurl 
  Title (down) Performance of NbN lattice‐cooled hot‐electron bolometric mixers Type Journal Article
  Year 1996 Publication J. Appl. Phys. Abbreviated Journal J. Appl. Phys.  
  Volume 80 Issue 7 Pages 4232-4234  
  Keywords NbN HEB mixers  
  Abstract The heterodyne performance of lattice‐cooled hot‐electron bolometric mixers is measured at 200 GHz. Superconducting thin‐film niobium nitride strips with ∼5 nm thickness are used as waveguide mixer elements. A double‐sideband receiver noise temperature of 750 K at 244 GHz is measured at an intermediate frequency centered at 1.5 GHz with 500 MHz bandwidth and with 4.2 K device temperature. The instantaneous bandwidth for this mixer is 1.6 GHz. The local oscillator power required by the mixer is about 0.5 μW. The mixer is linear to within 1 dB up to an input power level 6 dB below the local oscillator power. A receiver incorporating a hot‐electron bolometric mixer was used to detect molecular line emission in a laboratory gascell. This experiment unambiguously confirms that the receiver noise temperature determined from Y‐factor measurements reflects the true heterodyne sensitivity.  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0021-8979 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1607  
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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 (down) Parylene anti-reflection coating of a quasi-optical hot-electron-bolometric mixer at terahertz frequencies Type 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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  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 Hajenius, M.; Yang, Z. Q.; Gao, J. R.; Baselmans, J. J. A.; Klapwijk, T. M.; Voronov, B.; Gol'tsman, G. url  doi
openurl 
  Title (down) Optimized sensitivity of NbN hot electron bolometer mixers by annealing Type Journal Article
  Year 2007 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.  
  Volume 17 Issue 2 Pages 399-402  
  Keywords NbN HEB mixers  
  Abstract We report that the heterodyne sensitivity of superconducting hot-electron bolometers (HEBs) increases by 25-30% after annealing at 85degC in high vacuum. The devices studied are twin-slot antenna coupled mixers with a small area NbN bridge of 1 mum times 0.15 mum, above which there is a SiO 2 passivation layer. The mixer noise temperature, gain, and resistance versus temperature curve of a HEB before and after annealing are compared and analysed. We show that the annealing reduces the intrinsic noise of the mixer by 37% and makes the superconducting transition of the bridge and the contacts sharper. We argue that the reduction ofthe noise is mainly due to the improvement of the transparency of the contact/film interface. The lowest receiver noise temperature of 700 K is measured at a local oscillator frequency of 1.63 THz and at a bath temperature of 4.2 K.  
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  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 1426  
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