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Author González, F. J.; Boreman, G. D. openurl 
  Title Comparison of dipole, bowtie, spiral and log-periodic IR antennas Type Journal Article
  Year 2005 Publication Infrared Physics & Technology Abbreviated Journal Inf Phys & Technol  
  Volume 46 Issue 5 Pages 418-428  
  Keywords optical antennas; Microbolometer; Infrared antennas; Antenna efficiency; Antenna-coupled detectors  
  Abstract Antenna-coupled microbolometers use planar lithographic antennas to couple infrared radiation into a bolometer with sub-micron dimensions. In this paper four different types of infrared antennas were fabricated on thin grounded-substrates and coupled to microbolometers. Dipole, bowtie, spiral and log-periodic IR antenna-coupled detectors were measured at 10.6 μm and their performance compared. A new method to calculate the radiation efficiency based on the spatial and angular response of infrared antennas is presented and used to evaluate their performance. The calculated radiation efficiency for the dipole, bowtie, spiral and log-periodic IR antennas was 20%, 37%, 25% and 46% respectively. A dipole-length study was performed and shows that the quasistatic value of the effective permittivity accurately describes the incident wavelength in the substrate at infrared frequencies for antennas on a thin substrate.  
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  Notes Approved no  
  Call Number RPLAB @ gujma @ Serial (up) 739  
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Author Doerr, C.R.; Zhang, C.; Winzer, P.J. openurl 
  Title Monolithic InP multi-wavelength coherent receiver Type Conference Article
  Year 2010 Publication Conference on optical fiber communication, collocated national fiber optic engineers conference Abbreviated Journal Conf. OFC/NFOEC  
  Volume Issue Pages 1-3  
  Keywords InP balanced detector, waveguide grating, polarization splitter, from chiralphotonics  
  Abstract We propose and demonstrate a novel four-channel monolithic polarization-diversity dual-quadrature coherent receiver with balanced detection in InP. It uses an interleave-chirped arrayed waveguide grating that acts simultaneously as a demultiplexer, 90° hybrid, and polarization splitter.  
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  Notes Approved no  
  Call Number Serial (up) 851  
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Author Il'in, K. S.; Lindgren, M.; Currie, M. A.; Semenov, D.; Gol'tsman, G. N.; Sobolewski, Roman; Cherednichenko, S. I.; Gershenzon, E. M. url  doi
openurl 
  Title Picosecond hot-electron energy relaxation in NbN superconducting photodetectors Type Journal Article
  Year 2000 Publication Appl. Phys. Lett. Abbreviated Journal Appl. Phys. Lett.  
  Volume 76 Issue 19 Pages 2752-2754  
  Keywords NbN HEB detectors, two-temperature model, IF bandwidth  
  Abstract We report time-resolved characterization of superconducting NbN hot-electron photodetectors using an electro-optic sampling method. Our samples were patterned into micron-size microbridges from 3.5-nm-thick NbN films deposited on sapphire substrates. The devices were illuminated with 100 fs optical pulses, and the photoresponse was measured in the ambient temperature range between 2.15 and 10.6 K (superconducting temperature transition TC). The experimental data agreed very well with the nonequilibrium hot-electron, two-temperature model. The quasiparticle thermalization time was ambient temperature independent and was measured to be 6.5 ps. The inelastic electron–phonon scattering time Ï„e–ph tended to decrease with the temperature increase, although its change remained within the experimental error, while the phonon escape time Ï„es decreased almost by a factor of two when the sample was put in direct contact with superfluid helium. Specifically, Ï„e–ph and Ï„es, fitted by the two-temperature model, were equal to 11.6 and 21 ps at 2.15 K, and 10(±2) and 38 ps at 10.5 K, respectively. The obtained value of Ï„e–ph shows that the maximum intermediate frequency bandwidth of NbN hot-electron phonon-cooled mixers operating at TC can reach 16(+4/–3) GHz if one eliminates the bolometric phonon-heating effect.  
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  ISSN 0003-6951 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial (up) 856  
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Author D. Henrich, L. Rehm S. Dörner, M. Hofherr, K. Il'in, A. Semenov, and M. Siegel url  openurl
  Title Detection efficiency of a spiral-nanowire superconducting single-photon detector Type Journal Article
  Year 2012 Publication Abbreviated Journal  
  Volume Issue Pages  
  Keywords Critical current, Nanoscale devices, Superconducting photodetectors.  
  Abstract We investigate the detection efficiency of a spiral layout of a Superconducting Nanowire Single-Photon Detector (SNSPD). The design is less susceptible to the critical current reduction in sharp turns of the nanowire than the conventional meander design. Detector samples with different nanowire width from 300 to 100 nm are patterned from a 4 nm thick NbN film deposited on sapphire substrates. The critical current IC at 4.2 K for spiral, meander, and simple bridge structures is measured and compared. On the 100 nm wide samples, the detection efficiency is measured in the wavelength range 400-1700 nm and the cut-off wavelength of the hot-spot plateau is determined. In the optical range, the spiral detector reaches a detection efficiency of 27.6%, which is ~1.5 times the value of the meander. In the infrared range the detection efficiency is more than doubled.  
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  Corporate Author D. Henrich, L. Rehm S. Dörner, M. Hofherr, K. Il'in, A. Semenov, and M. Siegel Thesis  
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  Notes Approved no  
  Call Number RPLAB @ seleznev @ Serial (up) 880  
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Author Cherednichenko, Sergey; Drakinskiy, Vladimir; Berg, Therese; Khosropanah, Pourya; Kollberg, Erik openurl 
  Title Hot-electron bolometer terahertz mixers for the Herschel Space Observatory Type Journal Article
  Year 2008 Publication Review of Scientific Instruments Abbreviated Journal Rev. Sci. Instrum.  
  Volume 79 Issue Pages 034501  
  Keywords HEB mixer, HEB detector, HEB direct detector, applications  
  Abstract We report on low noise terahertz mixers(1.4–1.9THz) developed for the heterodyne spectrometer onboard the Herschel Space Observatory. The mixers employ double slot antenna integrated superconducting hot-electron bolometers (HEBs) made of thin NbN films. The mixer performance was characterized in terms of detection sensitivity across the entire rf band by using a Fourier transform spectrometer (from 0.5to2.5THz, with 30GHz resolution) and also by measuring the mixernoise temperature at a limited number of discrete frequencies. The lowest mixernoise temperature recorded was 750K [double sideband (DSB)] at 1.6THz and 950KDSB at 1.9THz local oscillator (LO) frequencies. Averaged across the intermediate frequency band of 2.4–4.8GHz, the mixernoise temperature was 1100KDSB at 1.6THz and 1450KDSB at 1.9THz LO frequencies. The HEB heterodyne receiver stability has been analyzed and compared to the HEB stability in the direct detection mode. The optimal local oscillator power was determined and found to be in a 200–500nW range.  
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  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial (up) 908  
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