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Author Pineda, J. L.; Velusamy, T.; Langer, W. D.; Goldsmith, P. F.; Li, D.; Yorke, H. W. doi  openurl
  Title A sample of [C II] clouds tracing dense clouds in weak FUV fields observed by Herschel Type Journal Article
  Year 2010 Publication (up) Astron. Astrophys. Abbreviated Journal  
  Volume 521 Issue Pages L19  
  Keywords HEB mixer applications, HIFI, Herschel, ISM: structure / photon-dominated region / ISM: supernova remnants / evolution  
  Abstract The [C ii] fine-structure line at 158 μm is an excellent tracer of the warm diffuse gas in the ISM and the interfaces between molecular clouds and their surrounding atomic and ionized envelopes. Here we present the initial results from Galactic observations of terahertz C+ (GOT C+), a Herschel key project devoted to studying the [C ii] emission in the Galactic plane using the HIFI instrument. We used the [C ii] emission, together with observations of CO, as a probe to understand the effects of newly formed stars on their interstellar environment and characterize the physical and chemical state of the star-forming gas. We collected data along 16 lines-of-sight passing near star-forming regions in the inner Galaxy near longitudes 330° and 20°. We identified fifty-eight [C ii] components that are associated with high-column density molecular clouds as traced by 13CO emission. We combined [C ii], 12CO, and 13CO observations to derive the physical conditions of the [C ii]-emitting regions in our sample of high-column density clouds based on comparing results from a grid of photon dominated region (PDR) models. From this unbiased sample, our results suggest that most of the [C ii] emission originates in clouds with H2 volume densities between 103.5 and 105.5 cm-3 and weak FUV strength (χ0 = 1–10). We find two regions where our analysis suggest high densities >105 cm-3 and strong FUV fields (χ0 = 104–106), likely associated with massive star formation. We suggest that [C ii] emission in conjunction with CO isotopes is a good tool for differentiating regions of massive star formation (high densities/strong FUV fields) and regions that are distant from massive stars (lower densities/weaker FUV fields) along the line-of-sight.  
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  Call Number Serial 1101  
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Author Velusamy, T.; Langer, W. D.; Pineda, J. L.; Goldsmith, P. F.; Li, D.; Yorke, H. W. doi  openurl
  Title [CII] observations of H2 molecular layers in transition clouds Type Journal Article
  Year 2010 Publication (up) Astron. Astrophys. Abbreviated Journal  
  Volume 521 Issue Pages L18  
  Keywords HEB mixer applications, HIFI, Herschel, ISM: structure / ISM: molecules / ISM: atoms / submillimeter: ISM  
  Abstract We present the first results on the diffuse transition clouds observed in [CII] line emission at 158 μm (1.9 THz) towards Galactic longitudes near 340° (5 LOSs) & 20° (11 LOSs) as part of the HIFI tests and GOT C+ survey. Out of the total 146 [CII] velocity components detected by profile fitting we identify 53 as diffuse molecular clouds with associated 12CO emission but without 13CO emission and characterized by AV < 5 mag. We estimate the fraction of the [CII] emission in the diffuse HI layer in each cloud and then determine the [CII] emitted from the molecular layers in the cloud. We show that the excess [CII] intensities detected in a few clouds is indicative of a thick H2 layer around the CO core. The wide range of clouds in our sample with thin to thick H2 layers suggests that these are at various evolutionary states characterized by the formation of H2 and CO layers from HI and C+, respectively. In about 30% of the clouds the H2 column densities (“dark gas”) traced by the [CII] is 50% or more than that traced by 12CO emission. On the average ~25% of the total H2 in these clouds is in an H2 layer which is not traced by CO. We use the HI, [CII], and 12CO intensities in each cloud along with simple chemical models to obtain constraints on the FUV fields and cosmic ray ionization rates.  
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  Call Number Serial 1102  
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Author Wampfler, S. F.; Herczeg, G. J.; Bruderer, S.; Benz, A. O.; van Dishoeck, E. F.; Kristensen, L. E.; Visser, R.; Doty, S. D.; Melchior, M.; van Kempen, T. A.; Yıldız, U. A.; Dedes, C.; Goicoechea, J. R.; Baudry, A.; Melnick, G.; Bachiller, R.; Benedettini, M.; Bergin, E.; Bjerkeli, P.; Blake, G. A.; Bontemps, S.; Braine, J.; Caselli, P.; Cernicharo, J.; Codella, C.; Daniel, F.; di Giorgio, A. M.; Dominik, C.; Encrenaz, P.; Fich, M.; Fuente, A.; Giannini, T.; de Graauw, Th.; Helmich, F.; Herpin, F.; Hogerheijde, M. R.; Jacq, T.; Johnstone, D.; Jørgensen, J. K.; Larsson, B.; Lis, D.; Liseau, R.; Marseille, M.; Mc Coey, C.; Neufeld, D.; Nisini, B.; Olberg, M.; Parise, B.; Pearson, J. C.; Plume, R.; Risacher, C.; Santiago-García, J.; Saraceno, P.; Shipman, R.; Tafalla, M.; van der Tak, F. F. S.; Wyrowski, F.; Roelfsema, P.; Jellema, W.; Dieleman, P.; Caux, E.; Stutzki, J. doi  openurl
  Title Herschel observations of the hydroxyl radical (OH) in young stellar objects Type Journal Article
  Year 2010 Publication (up) Astron. Astrophys. Abbreviated Journal  
  Volume 521 Issue Pages L36  
  Keywords HEB mixer applications, HIFI, Herschel, astrochemistry / stars: formation / ISM: molecules / ISM: jets and outflows / ISM: individual objects: HH 46  
  Abstract Aims. “Water In Star-forming regions with Herschel” (WISH) is a Herschel key program investigating the water chemistry in young stellar objects (YSOs) during protostellar evolution. Hydroxyl (OH) is one of the reactants in the chemical network most closely linked to the formation and destruction of H2O. High-temperature (T 250 K) chemistry connects OH and H2O through the OH + H2 H2O + H reactions. Formation of H2O from OH is efficient in the high-temperature regime found in shocks and the innermost part of protostellar envelopes. Moreover, in the presence of UV photons, OH can be produced from the photo-dissociation of H2O through H2O + γUV OH + H.

Methods. High-resolution spectroscopy of the 163.12 μm triplet of OH towards HH 46 and NGC 1333 IRAS 2A was carried out with the Heterodyne Instrument for the Far Infrared (HIFI) on board the Herschel Space Observatory. The low- and intermediate-mass protostars HH 46, TMR 1, IRAS 15398-3359, DK Cha, NGC 7129 FIRS 2, and NGC 1333 IRAS 2A were observed with the Photodetector Array Camera and Spectrometer (PACS) on Herschel in four transitions of OH and two [O i] lines.

Results. The OH transitions at 79, 84, 119, and 163 μm and [O i] emission at 63 and 145μm were detected with PACS towards the class I low-mass YSOs as well as the intermediate-mass and class I Herbig Ae sources. No OH emission was detected from the class 0 YSO NGC 1333 IRAS 2A, though the 119 μm was detected in absorption. With HIFI, the 163.12 μm was not detected from HH 46 and only tentatively detected from NGC 1333 IRAS 2A. The combination of the PACS and HIFI results for HH 46 constrains the line width (FWHM 11 km s-1) and indicates that the OH emission likely originates from shocked gas. This scenario is supported by trends of the OH flux increasing with the [O i] flux and the bolometric luminosity, as found in our sample. Similar OH line ratios for most sources suggest that OH has comparable excitation temperatures despite the different physical properties of the sources.
 
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  Call Number Serial 1103  
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Author Shangina, E. L.; Smirnov, K. V.; Morozov, D. V.; Kovalyuk, V. V.; Gol’tsman, G. N.; Verevkin, A. A.; Toropov, A. I. url  doi
openurl 
  Title Concentration dependence of the intermediate frequency bandwidth of submillimeter heterodyne AlGaAs/GaAs nanostructures Type Journal Article
  Year 2010 Publication (up) Bull. Russ. Acad. Sci. Phys. Abbreviated Journal Bull. Russ. Acad. Sci. Phys.  
  Volume 74 Issue 1 Pages 100-102  
  Keywords 2DEG AlGaAs/GaAs heterostructures, THz heterodyne detectors, IF bandwidth  
  Abstract The concentration dependence of the intermediate frequency bandwidth of heterodyne AlGaAs/GaAs detectors with 2D electron gas is measured using submillimeter spectroscopy with high time resolution at T= 4.2 K. The intermediate frequency bandwidth f3dBfalls from 245 to 145 MHz with increasing concentration of 2D electrons n s = (1.6-6.6) × 10[su11] cm-2. The dependence f3dB ≈ n s – 0.04±is observed in the studied concentration range; this dependence is determined by electron scattering by the deformation potential of acoustic phonons and piezoelectric scattering.  
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  Series Volume Series Issue Edition  
  ISSN 1062-8738 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1217  
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Author Lee, B. G.; Doany, F. E.; Assefa, S.; Green, W.; Yang, M.; Schow, C. L.; Jahnes, C. V.; Zhang, S.; Singer, J.; Kopp, V. I.; Kash, J. A.; Vlasov, Y. A. openurl 
  Title 20-μm-pitch eight-channel monolithic fiber array coupling 160 Gb/s/channel to silicon nanophotonic chip Type Conference Article
  Year 2010 Publication (up) Conf. OFC/NFOEC Abbreviated Journal Conf. OFC/NFOEC  
  Volume Issue Pages 1-3  
  Keywords spot size converters, SSC, optical waveguides, optical fiber waveguides, ultra-dense silicon waveguide arrays, silicon waveguides, waveguide arrays, from chiralphotonics  
  Abstract A multichannel tapered coupler interfacing standard 250-μm-pitch low-NA polarization-maintaining fiber arrays with ultra-dense 20-μm-pitch high-NA silicon waveguides is designed, fabricated, and tested, demonstrating coupling losses below 1 dB and injection bandwidths of 160 Gb/s/channel.  
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  Area Expedition Conference Conference on optical fiber communication, collocated national fiber optic engineers conference  
  Notes Approved no  
  Call Number Serial 852  
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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 (up) 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 851  
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Author Yamashita, Taro; Miki, Shigehito; Qiu, Wei; Fujiwara, Mikio; Sasaki, Masahide; Wang, Zhen openurl 
  Title Temperature dependent performances of superconducting nanowire single-photon detectors in an ultralow-temperature region Type Journal Article
  Year 2010 Publication (up) IEEE Trans. Appl. Supercond. Abbreviated Journal  
  Volume 21 Issue 3 Pages 336 - 339  
  Keywords SNSPD  
  Abstract We report on the performance of a fiber-coupled superconducting nanowire single-photon detector (SNSPD) from 4 K down to the ultralow temperature of 16 mK for a 1550 nm wave length. The system detection efficiency (DE) increased with de creasing the temperature and reached the considerably high value of 15% with a dark count rate less than 100 cps below 1.5 K, even without an optical cavity structure. We also observed saturation of the system DE in its bias current dependency at 16 mK, which indicates that the device DE of our SNSPD nearly reached intrinsic DE despite the device having a large active area of 20 μm × 20 μm. The dark count was finite even at 16 mK and the black body radiation becomes its dominant origin in the low temperatures for fiber-coupled devices.  
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  Notes Approved no  
  Call Number RPLAB @ gujma @ Serial 656  
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Author Hoeffgen, S.K.; Kuhnhenn, J.; Weinand, U. openurl 
  Title High radiation sensitivity of chiral long period gratings Type Journal Article
  Year 2010 Publication (up) IEEE Trans. Nucl. Sci. Abbreviated Journal  
  Volume 57 Issue 5 Pages 2915 - 2922  
  Keywords chiral fiber gratings, chiral gratings, chiral LPG, from chiralphotonics  
  Abstract The radiation sensitivity of chiral long period gratings was investigated for the first time. After a Co-60 gamma dose of 100 kGy they show radiation-induced changes of their transmission dip wavelength of up to 10 nm, which is 100 to 1000 times higher than the radiation-induced wavelength shift of different fiber Bragg grating types. They can therefore be used as radiation sensors down to doses of 10 Gy or even below, but not for accurate dose measurements since the size of the wavelength shift after a certain dose still depends on the radiation dose rate. Chiral gratings made of eight single mode fiber types with differences of their radiation-induced attenuation of several orders of magnitude were investigated in order to look for a correlation between dip wavelength shift and fiber attenuation. However, the dip wavelength curves do not show exactly the same order as the fiber attenuation curves. A theory that can exactly predict all properties of the chiral gratings might enable us to specify from our results an optimized fiber for the production of gratings that can also be used for radiation dosimetry.  
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  Call Number Serial 848  
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Author Marsili, Francesco; Bitauld, David; Fiore, Andrea; Gaggero, Alessandro; Mattioli, Francesco; Leoni, Roberto; Divochiy, Aleksander; Gol'tsman, Gregory url  doi
openurl 
  Title Photon-number-resolution at telecom wavelength with superconducting nanowires Type Miscellaneous
  Year 2010 Publication (up) IntechOpen Abbreviated Journal  
  Volume Issue Pages  
  Keywords SSPD, SNSPD  
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  Notes Approved no  
  Call Number RPLAB @ sasha @ marsiliphoton Serial 1036  
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Author Annunziata, Anthony J.; Quaranta, Orlando; Santavicca, Daniel F.; Casaburi, Alessandro; Frunzio, Luigi; Ejrnaes, Mikkel; Rooks, Michael J.; Cristiano, Roberto; Pagano, Sergio; Frydman, Aviad; Prober, Daniel E. openurl 
  Title Reset dynamics and latching in niobium superconducting nanowire single-photon detectors Type Journal Article
  Year 2010 Publication (up) J. Appl. Phys. Abbreviated Journal  
  Volume 108 Issue 8 Pages 7  
  Keywords SNSPD  
  Abstract We study the reset dynamics of niobium (Nb) superconducting nanowire single-photon detectors (SNSPDs) using experimental measurements and numerical simulations. The numerical simulations of the detection dynamics agree well with experimental measurements, using independently determined parameters in the simulations. We find that if the photon-induced hotspot cools too slowly, the device will latch into a dc resistive state. To avoid latching, the time for the hotspot to cool must be short compared to the inductive time constant that governs the resetting of the current in the device after hotspot formation. From simulations of the energy relaxation process, we find that the hotspot cooling time is determined primarily by the temperature-dependent electron-phonon inelastic time. Latching prevents reset and precludes subsequent photon detection. Fast resetting to the superconducting state is, therefore, essential, and we demonstrate experimentally how this is achieved. We compare our results to studies of reset and latching in niobium nitride SNSPDs.  
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  Call Number RPLAB @ gujma @ Serial 649  
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Author Maingault, L.; Tarkhov, M.; Florya, I.; Semenov, A.; Espiau de Lamaëstre, R.; Cavalier, P.; Gol’tsman, G.; Poizat, J.-P.; Villégier, J.-C. url  doi
openurl 
  Title Spectral dependency of superconducting single photon detectors Type Journal Article
  Year 2010 Publication (up) J. Appl. Phys. Abbreviated Journal J. Appl. Phys.  
  Volume 107 Issue 11 Pages 116103 (1 to 3)  
  Keywords NbN SSPD, SNSPD  
  Abstract We investigate the effect of varying both incoming optical wavelength and width of NbN nanowires on the superconducting single photon detectors (SSPD) detection efficiency. The SSPD are current biased close to critical value and temperature fixed at 4.2 K, far from transition. The experimental results are found to verify with a good accuracy predictions based on the “hot spot model,” whose size scales with the absorbed photon energy. With larger optical power inducing multiphoton detection regime, the same scaling law remains valid, up to the three-photon regime. We demonstrate the validity of applying a limited number of measurements and using such a simple model to reasonably predict any SSPD behavior among a collection of nanowire device widths at different photon wavelengths. These results set the basis for designing efficient single photon detectors operating in the infrared (2–5 μm range).

This work was supported by European projects FP6 STREP “SINPHONIA” (Contract No. NMP4-CT-2005-16433) and IP “QAP” (Contract No. 15848).
 
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  ISSN 0021-8979 ISBN Medium  
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  Notes Approved no  
  Call Number Serial 1392  
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Author Jang, Young Rae; Yoo, Keon-Ho; Park, Seung Min openurl 
  Title Rapid thermal annealing of ZnO thin films grown at room temperature Type Journal Article
  Year 2010 Publication (up) J. Vac. Sci. Technol. A Abbreviated Journal  
  Volume 28 Issue 2 Pages 4  
  Keywords Annealing  
  Abstract The authors successfully obtained high quality ZnO thin films by growing them at room temperature (RT) and postannealing by rapid thermal annealing (RTA). The thin films were grown by pulsed laser deposition on Si (100) substrates at RT, and RTA was performed under various temperatures and ambient conditions. Based on the UV emission to visible emission ratio in RT photoluminescence (PL) spectra, the optimum film was obtained at annealing temperature ~700 °C in an ambient of Ar, N2, or O2 at 0.1 Torr, while the optimum annealing temperature was above 1100 °C in the air ambient at atmospheric pressure. The morphology and structure of the films in different RTA conditions were investigated by using field emission scanning electron microscopy and grazing incidence x-ray diffraction, and were discussed in conjunction with the PL data.  
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  Notes Annealing Approved no  
  Call Number RPLAB @ gujma @ Serial 692  
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Author Smirnov, K. V.; Vakhtomin, Yu. B.; Divochiy, A. V.; Ozhegov, R. V.; Pentin, I. V.; Gol'tsman, G. N. url  doi
openurl 
  Title Infrared and terahertz detectors on basis of superconducting nanostructures Type Conference Article
  Year 2010 Publication (up) Microwave and Telecom. Technol. (CriMiCo), 20th Int. Crimean Conf. Abbreviated Journal  
  Volume Issue Pages 823-824  
  Keywords SSPD, SNSPD, HEB  
  Abstract Results of development of single-photon receiving systems of visible, infrared and terahertz range based on thin-film superconducting nanostructures are presented. The receiving systems are produced on the basis of superconducting nanostructures, which function by means of hot-electron phenomena.  
  Address  
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  Publisher Place of Publication Editor IEEE  
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  Notes Approved no  
  Call Number RPLAB @ sasha @ smirnov2010infrared Serial 1025  
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Author Diana Prado Lopes Aude openurl 
  Title Modeling superconductors using surface impedance technique Type Book Whole
  Year 2010 Publication (up) MIT Abbreviated Journal MIT  
  Volume Issue Pages  
  Keywords homogeneous isotropic BCS superconductor complex conductivity superconductor surface impedance  
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  Notes Approved no  
  Call Number Serial 938  
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Author O'Neal, Claire openurl 
  Title A project guide to rocks and minerals Type Book Whole
  Year 2010 Publication (up) Mitchell Lane Publishers Abbreviated Journal  
  Volume Issue Pages 1-47  
  Keywords children  
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  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1147  
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