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Author Gol'tsman, G.; Kouminov, P.; Goghidze, I.; Gershenzon, E.
Title Nonequilibrium kinetic inductive response of YBCO thin films to low power laser pulses Type Journal Article
Year 1995 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.
Volume 5 Issue 2 Pages 2591-2594
Keywords YBCO HTS KID
Abstract (up) We have discovered a transient nonequilibrium kinetic inductive voltage response of YBCO thin films to 20 ps pulses of YAG:Nd laser radiation with 0.63 /spl mu/m and 1.54 /spl mu/m wavelength. By increasing the sensitivity of the read-out system with 100 ps resolution time and diminishing the light intensity (fluence 0.1-2 /spl mu/J/cm/sup 2/) and transport current (density /spl les/10/sup 5/ A/cm/sup 2/) we were able to observe a peculiar bipolar signal form with nearly equal amplitudes for each sign. The integration of the kinetic inductive response over time gives the result which is qualitatively, of the same form as the response in the resistive and normal states: the nonequilibrium picosecond scale component is followed by the bolometric nanosecond component. The nonequilibrium response is interpreted as suppression of the order parameter by excess quasiparticles followed by a change both in resistance (for the resistive state) and in kinetic inductance (for the superconducting state).
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 1051-8223 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1621
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Author Huebers, H.-W.; Schubert, J.; Semenov, A.; Gol’tsman, G. N.; Voronov, B. M.; Gershenzon, E. M.; Schwaab, G. W.
Title NbN phonon-cooled hot-electron bolometer as a mixer for THz heterodyne receivers Type Conference Article
Year 1999 Publication Proc. SPIE Abbreviated Journal Proc. SPIE
Volume 3828 Issue Pages 410-416
Keywords NbN HEB mixers
Abstract (up) We have investigated a phonon-cooled NbN hot electron bolometric (HEB) mixer in the frequency range from 0.7 THz to 5.2 THz. The device was a 3.5 nm thin film with an in- plane dimension of 1.7 X 0.2 micrometers 2 integrated in a complementary logarithmic spiral antenna. The measured DSB receiver noise temperatures are 1500 K, 2200 K, 2600 K, 2900 K, 4000 K, 5600 K and 8800 K. The sensitivity fluctuation, the long term stability, and the antenna pattern were measured and the suitability of the mixer for a practical heterodyne receiver is discussed.
Address
Corporate Author Thesis
Publisher Spie Place of Publication Editor Chamberlain, J.M.
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference Terahertz Spectroscopy and Applications II
Notes Approved no
Call Number Serial 1477
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Author Ekström, H.; Kollberg, E.; Yagoubov, P.; Gol'tsman, G.; Gershenzon, E.; Yngvesson, S.
Title Phonon cooled ultra thin NbN hot electron bolometer mixers at 620 GHz Type Conference Article
Year 1997 Publication Proc. 8th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 8th Int. Symp. Space Terahertz Technol.
Volume Issue Pages 29-35
Keywords NbN HEB mixers
Abstract (up) We have measured the noise performance and gain bandwidth of 35 A thin NbN hot-electron mixers integrated with spiral antennas on silicon substrate lenses at 620 GHz. A double-sideband receiver noise temperature less than 1300 K has been obtained with a 3 dB bandwidth of GHz. The gain bandwidth is 3.2 GHz. A lower noise temperature of 1100 K has been achieved with an improved set-up. The mixer output noise dominated by thermal fluctuations is about 50-60 K, and the SSB receiver and intrinsic conversion gain is about -18 and -12 dB, respectively. Without mismatch losses and excluding the loss from the beamsplitter, we expect to achieve a receiver noise temperature of less than 700 K.
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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 Serial 1604
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Author Ekstörm, H.; Kollberg, E.; Yagoubov, P.; Gol'tsman, G.; Gershenzon, E.; Yngvesson, S.
Title Gain and noise bandwidth of NbN hot-electron bolometric mixers Type Journal Article
Year 1997 Publication Appl. Phys. Lett. Abbreviated Journal Appl. Phys. Lett.
Volume 70 Issue 24 Pages 3296-3298
Keywords NbN HEB mixers, conversion loss, conversion gain, U-factor technique
Abstract (up) We have measured the noise performance and gain bandwidth of 35 Å thin NbN hot-electron mixers integrated with spiral antennas on silicon substrate lenses at 620 GHz. The best double-sideband receiver noise temperature is less than 1300 K with a 3 dB bandwidth of ≈5 GHz. The gain bandwidth is 3.2 GHz. The mixer output noise dominated by thermal fluctuations is 50 K, and the intrinsic conversion gain is about −12 dB. Without mismatch losses and excluding the loss from the beamsplitter, we expect to achieve a receiver noise temperature of less than 700 K.
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 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 279
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Author Ekström, H.; Kroug, M.; Belitsky, V.; Kollberg, E.; Olsson, H.; Goltsman, G.; Gershenzon, E.; Yagoubov, P.; Voronov, B.; Yngvesson, S.
Title Hot electron mixers for THz applications Type Conference Article
Year 1996 Publication Proc. 30th ESLAB Abbreviated Journal Proc. 30th ESLAB
Volume Issue Pages 207-210
Keywords NbN HEB mixers
Abstract (up) We have measured the noise performance of 35 A thin NbN HEB devices integrated with spiral antennas on antireflection coated silicon substrate lenses at 620 GHz. From the noise measurements we have determined a total conversion gain of the receiver of—16 dB, and an intrinsic conversion of about-10 dB. The IF bandwidth of the 35 A thick NbN devices is at least 3 GHz. The DSB receiver noise temperature is less than 1450 K. Without mismatch losses, which is possible to obtain with a shorter device, and with reduced loss from the beamsplitter, we expect to achieve a DSB receiver noise temperature of less ‘than 700 K.
Address Noordwijk, Netherlands
Corporate Author Thesis
Publisher Place of Publication Editor Rolfe, E. J.; Pilbratt, G.
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference Submillimetre and Far-Infrared Space Instrumentation
Notes Approved no
Call Number Serial 1606
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