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Author (up) Lindgren, M.; Currie, M.; Zeng, W.-S.; Sobolewski, R.; Cherednichenko, S.; Voronov, B.; Gol'tsman, G. N.
Title Picosecond response of a superconducting hot-electron NbN photodetector Type 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.
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ISSN 0964-1807 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1584
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Author (up) Maddison, B. J.; Martin, R. J.; Oldfield, M. L.; Mann, C. M.; Matheson, D. N.; Ellison, B. N.; Thornton, J.; Hall, W. J.; Lamarre, D. M.
Title A compact 500 GHz planar schottky siode receiver with a wide instantaneous bandwidth Type Conference Article
Year 1998 Publication Proc. 9th Int. Symp. Space Terahertz Technol. Abbreviated Journal
Volume Issue Pages 367
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Notes Approved no
Call Number RPLAB @ s @ schottky_Tn_4800_at_p5THz Serial 286
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Author (up) Mann, C. M.; Matheson, D. N.; Ellison, B. N.; Oldfield, M. L.; Moyna, B. P.; Spencer, J. J.; Wilsher, D. S.; Maddison, B. J.
Title On the design and measurement of a 2.5 THz waveguide mixer Type Conference Article
Year 1998 Publication Proc. 9th Int. Symp. Space Terahertz Technol. Abbreviated Journal
Volume Issue Pages 161
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Notes Approved no
Call Number RPLAB @ s @ schottky_Tn_16800_at_2p5THz Serial 283
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Author (up) Merkel, H. F.; Yagoubov, P. A.; Kroug, M.; Khosropanah, P.; Kollberg, E. L.; Gol’tsman, G. N.; Gershenzon, E. M.
Title Noise temperature and absorbed LO power measurement methods for NbN phonon-cooled hot electron bolometric mixers at terahertz frequencies Type Conference Article
Year 1998 Publication Proc. 28th European Microwave Conf. Abbreviated Journal Proc. 28th European Microwave Conf.
Volume 1 Issue Pages 294-299
Keywords NbN HEB mixers
Abstract In this paper the absorbed LO power requirements and the noise performance of NbN based phonon-cooled hot electron bolometric (HEB) quasioptical mixers are investigated for RF frequencies in the 0.55-1.1 range The minimal measured DSB noise temperatures are about 500 K at 640 GHz, 600 K at 750 GHz, 850 K at 910 GHz and 1250 K at 1.1 THz. The increase in noise temperature at 1.1THz is attributed to water absorption. The absorbed LO power is measured using a calorimetric approach. The results are subsequently corrected for lattice heating. These values are compared to results of a novel one dimensional hot spot mixer models and to a more traditional isotherm method which tends to underestimate the absorbed LO power for small bias powers. Typically a LO power between 50nW and 100nW is needed to pump the device to the optimal operating point.
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Area Expedition Conference 28th European Microwave Conference
Notes Approved no
Call Number Serial 1580
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Author (up) Schwaab, G.W.; Auen, K.; Bruendermann, E.; Feinaeugle, R.; Gol’tsman, G.N.; Huebers, H.-W.; Krabbe, A.; Roeser, H.-P.; Sirmain, G.
Title 2- to 6-THz heterodyne receiver array for the Stratospheric Observatory for Infrared Astronomy (SOFIA) Type Conference Article
Year 1998 Publication Proc. SPIE Abbreviated Journal Proc. SPIE
Volume 3357 Issue Pages 85-96
Keywords NbN HEB mixers, applications, stratospheric observatory, airborne
Abstract The Institute of Space Sensor Technology of the German Aerospace Center (DLR) is developing a heterodyne array receiver for the frequency range 2 to 6 THz for the Stratospheric Observatory for Infrared Astronomy (SOFIA). Key science issues in that frequency range are the observation of lines of atoms [e.g. (OI)], ions [e.g. (CII), (NII)], and molecules (e.g. OH, HD, CO) with high spectral resolution to study the dynamics and evolution of galactic and extragalactic objects. Long term goal is the development of an integrated array heterodyne receiver with superconducting hot electron bolometric (HEB) mixers and p-type Ge or Si lasers as local oscillators. The first generation receiver will be composed of HEB mixers in a 2 pixel 2 polarization array which will be pumped by a gas laser local oscillator. Improved Schottky diode mixers are the backup solution for the HEBs. The state of the art of HEB mixer and p-type Ge laser technology are described as well as possible improvements in the ’conventional’ optically pumped far-infrared laser and Schottky diode mixer technology. Finally, the frequency coverage of the first generation heterodyne receiver for some important astronomical transitions is discussed. The expected sensitivity is compared to line fluxes measured by the ISO satellite.
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Publisher SPIE Place of Publication Editor Phillips, T.G.
Language Summary Language Original Title
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Area Expedition Conference Advanced Technology MMW, Radio, and Terahertz Telescopes
Notes Approved no
Call Number Serial 1583
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