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Author (up) Karpov, A.; Miller, D.; Stern, J. A.; Bumble, B.; LeDuc, H. G.; Zmuidzinas, J. openurl 
  Title Broadband SIS mixer for 1 THz Band Type Conference Article
  Year 2009 Publication Proc. 20th Int. Symp. Space Terahertz Technol. Abbreviated Journal  
  Volume Issue Pages 35-35  
  Keywords SIS mixer, noise temperature  
  Abstract We report the development of a low noise and broadband SIS mixer aimed for 1 THz channel of the Caltech Airborne Submillimeter Interstellar Medium Investigations Receiver (CASIMIR), designed for the Stratospheric Observatory for Far Infrared Astronomy, (SOFIA). The mixer uses an array of 0.24 µm² Nb/Al-AlN/NbTiN SIS junctions with critical current density of 30-50 KA/cm². The junctions are shaped in order to optimize the suppression of the Josephson DC currents. We are using a double slot planar antenna to couple the mixer chip with the telescope beam. The RF matching microcircuit is made using Nb and gold films. The mixer IF circuit is designed to cover 4 – 8 GHz band. A test receiver with the new mixer has a low noise operation in a 0.87 – 1.12 THz band. The minimum DSB receiver noise measured at 1 THz is 260 K (Y=1.64), apparently the lowest reported up to date. The receiver noise corrected for the loss in the LO injection beam splitter and in the cryostat window is 200 K. The combination of a broad operation band of about 250 GHz with a low receiver noise is making the new mixer a useful element for application at SOFIA. We will discuss the prospective of a further improvement of the sensitivity and extension of the upper frequency of operation of SIS mixer.  
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  Notes Approved no  
  Call Number Serial 614  
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Author (up) Karpowicz, Nicholas; Lu, Xiaofei; Zhang, X.-C. openurl 
  Title Terahertz gas photonics Type Journal Article
  Year 2009 Publication J. Modern Opt. Abbreviated Journal  
  Volume 56 Issue 10 Pages 1137-1150  
  Keywords  
  Abstract The underlying physics of the generation and detection of terahertz (THz) waves in gases are described. The THz wave generation process takes place in two steps: asymmetric gas ionization by two-frequency laser fields, followed by interaction of the ionized electron wave packets with the surrounding medium, producing an intense ‘echo' with tunable spectral content. In order to clarify the physical picture at the moment of ionization, the laser–atom interaction is treated through solution of the time-dependent Schrödinger equation, yielding an ab initio understanding of the release of the electron wave packets. The second step, where the electrons interact with the surrounding plasma is treated analytically. The resulting pressure dependence of the THz radiation is explored in detail. The THz wave detection process is shown to be the result of four-wave mixing, leading to analytical expressions of the signal obtained which allow for improved optimization of systems that exploit these effects.  
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  Notes Approved no  
  Call Number RPLAB @ gujma @ Serial 670  
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Author (up) Kerman, Andrew J.; Yang, Joel K. W.; Molnar, Richard J.; Dauler, Eric A.; Berggren, Karl K. openurl 
  Title Electrothermal feedback in superconducting nanowire single-photon detectors Type Journal Article
  Year 2009 Publication Phys. Rev. B Abbreviated Journal Phys. Rev. B  
  Volume 79 Issue 10 Pages 4  
  Keywords SNSPD  
  Abstract We investigate the role of electrothermal feedback in the operation of superconducting nanowire single-photon detectors (SNSPDs). It is found that the desired mode of operation for SNSPDs is only achieved if this feedback is unstable, which happens naturally through the slow electrical response associated with their relatively large kinetic inductance. If this response is sped up in an effort to increase the device count rate, the electrothermal feedback becomes stable and results in an effect known as latching, where the device is locked in a resistive state and can no longer detect photons. We present a set of experiments which elucidate this effect and a simple model which quantitatively explains the results.  
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  Notes Approved no  
  Call Number RPLAB @ gujma @ Serial 680  
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Author (up) Kern, Pierre; Le Coärer, Etienne; Benech, Pierre openurl 
  Title On-chip spectro-detection for fully integrated coherent beam combiners Type Journal Article
  Year 2009 Publication Optics Express Abbreviated Journal Opt.Express  
  Volume 17 Issue 3 Pages 1976-1987  
  Keywords  
  Abstract This paper presents how photonics associated with new arising detection technologies is able to provide fully integrated instrument for coherent beam combination applied to astrophysical interferometry. The feasibility and operation of on-chip coherent beam combiners has been already demonstrated using various interferometric combination schemes. More recently we proposed a new detection principle aimed at directly sampling and extracting the spectral information of an input signal together with its flux level measurement. The so-called SWIFTS demonstrated concept that stands for Stationary-Wave Integrated Fourier Transform Spectrometer, provides full spectral and spatial information recorded simultaneously thanks to a motionless detecting device. Due to some newly available detection principles considered for the implementation of the SWIFTS concept, some technologies can even provide photo-counting operation that brought a significant extension of the interferometry domain of investigation in astrophysics. The proposed concept is applicable to most of the interferometric instrumental modes including fringe tracking, fast and sensitive detection, Fourier spectral reconstruction and also to manage a large number of incoming beams. The paper presents three practical implementations, two dealing with pair-wise integrated optics beam combinations and the third one with an all-in-one 8 beam combination. In all cases the principles turned into a pair wise baseline coding after proper data processing.  
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  Notes Approved no  
  Call Number RPLAB @ gujma @ Serial 650  
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Author (up) Khosropanah P.; Baryshev A.; Zhang W.; Jellema W.; Hovenier J.N.; Gao G.R.; Klapwijk T.M; Paveliev D.G.; Williams B.S.; Kumar S.; Hu Q.; Reno J.L.; Klein B.; Hesler J.L. openurl 
  Title Phase-locking of a 2.7-THz quantum cascade laser to a microwave reference Type Journal Article
  Year 2009 Publication Optics Letters Abbreviated Journal  
  Volume 34 Issue Pages 2958-2960  
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  Abstract We demonstrate the phase locking of a 2.7 THz metal–metal waveguide quantum cascade laser (QCL) to an external microwave signal. The reference is the 15th harmonic, generated by a semiconductor superlattice nonlinear device, of a signal at 182 GHz, which itself is generated by a multiplier chain (X12) from a

microwave synthesizer at ~ 15 GHz. Both laser and reference radiations are coupled into a bolometer mixer, resulting in a beat signal, which is fed into a phase-lock loop. The spectral analysis of the beat signal con-firms that the QCL is phase locked. This result opens the possibility to extend heterodyne interferometers into the far-infrared range.
 
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  Notes Approved no  
  Call Number RPLAB @ atomics90 @ Serial 966  
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Author (up) Li, Chao-Te; Chen, Tse-Jun; Ni, Tong-Liang; Lu, Wei-Chun; Chiu, Chuang-Ping; Chen, Chong-Wen; Chang, Yung-Chin; Wang, Ming-Jye Shi, Sheng-Cai openurl 
  Title Development of SIS mixers for SMA 400-520 GHz band Type Conference Article
  Year 2009 Publication Proc. 20th Int. Symp. Space Terahertz Technol. Abbreviated Journal  
  Volume Issue Pages 24-30  
  Keywords SIS mixer, noise temperature, SMA  
  Abstract SIS junction mixers were developed for SMA 400-520 GHz band. The results show receiver noise temperature around 100 K across the band, with noise contribution from RF loss and IF estimated to be around 50 K and 20K, respectively. Two schemes were used to tune out junction's parasitic capacitance. When a parallel inductor is employed, the input impedance is close to Rn, which facilitates impedance matching between the junction and the waveguide probe. Waveguide probes were designed to achieve a low feed-point impedance to match to the junction resistance. Optimum embedding impedances for lower receiver noise temperature were investigated. Performances of two schemes and composition of receiver noise were also discussed.  
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  Notes Approved no  
  Call Number Serial 617  
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Author (up) Lieberzeit, Peter A.; Dickert, Franz L. url  doi
openurl 
  Title Chemosensors in environmental monitoring: challenges in ruggedness and selectivity Type Journal Article
  Year 2009 Publication Analytical and Bioanalytical Chemistry Abbreviated Journal Anal Bioanal Chem  
  Volume 393 Issue 2 Pages 467-472  
  Keywords environmental monitoring, in situ sensing, artificial recognition materials, real-life application, molecular imprinting, QCM  
  Abstract Environmental analysis is a potential key application for chemical sensors owing to their inherent ability to detect analytes on-line and in real time in distributed systems. Operating a chemosensor in a natural environment poses substantial challenges in terms of ruggedness, long-term stability and calibration. This article highlights current trends of achieving both the necessary selectivity and ruggedness: one way is deploying sensor arrays consisting of robust broadband sensors and extracting information via chemometrics. If using only a single sensor is desired, molecularly imprinted polymers offer a straightforward way for designing artificial recognition materials. Molecularly imprinted polymers can be utilized in real-life environments, such as water and air, aiming at detecting analytes ranging from small molecules to entire cells.  
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  Series Volume Series Issue Edition  
  ISSN 1618-2642 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 564  
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Author (up) Lobanov, Y.; Tong, C.; Blundell, R.; Gol'tsman, G. url  openurl
  Title A study of direct detection effect on the linearity of hot electron bolometer mixers Type Conference Article
  Year 2009 Publication Proc. 20th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 20th ISSTT  
  Volume Issue Pages 282-287  
  Keywords HEB mixer, direct detection effect  
  Abstract We have performed a study of how direct detection affects the linearity and hence the calibration of an HEB mixer. Two types of waveguide HEB devices have been used: a 0.8 THz HEB mixer and a 1.0 THz HEB mixer which is ~5 times smaller than the former. Two independent experimental approaches were used. In the ΔG/G method, the conversion gain of the HEB mixer is first measured as a function of the bias current for a number of bias voltages. At each bias setting, we carefully measure the change in the operating current when the input loads are switched. From the measured data, we can derive the expected difference in gain between the hot and cold loads. In the second method (injection method [1]), the linearity of the HEB mixer is independently measured by injecting a modulated signal for different input load temperatures. The results of both approaches confirm that there is gain compression in the operation of HEB mixers. Based on the results of our measurements, we discuss the impact of direct detection effects on the operation of HEB mixers.  
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  Notes Approved no  
  Call Number RPLAB @ gujma @ Serial 724  
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Author (up) Marksteiner, M.; Divochiy, A.; Sclafani, M.; Haslinger, P.; Ulbricht, H.; Korneev, A.; Semenov, A.; Gol'tsman, G.; Arndt, M. url  doi
openurl 
  Title A superconducting NbN detector for neutral nanoparticles Type Journal Article
  Year 2009 Publication Nanotechnol. Abbreviated Journal Nanotechnol.  
  Volume 20 Issue 45 Pages 455501  
  Keywords SSPD; SNSPD; *Electric Conductivity; Microscopy, Electron, Scanning; Nanoparticles/*chemistry/ultrastructure; Nanotechnology/*methods; *Photons  
  Abstract We present a proof-of-principle study of superconducting single photon detectors (SSPD) for the detection of individual neutral molecules/nanoparticles at low energies. The new detector is applied to characterize a laser desorption source for biomolecules and allows retrieval of the arrival time distribution of a pulsed molecular beam containing the amino acid tryptophan, the polypeptide gramicidin as well as insulin, myoglobin and hemoglobin. We discuss the experimental evidence that the detector is actually sensitive to isolated neutral particles.  
  Address University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria. markus.arndt@univie.ac.at  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0957-4484 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:19822928 Approved no  
  Call Number Serial 1239  
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Author (up) Marsili, F.; Bitauld, D.; Fiore, A.; Gaggero, A.; Leoni, R.; Mattioli, F.; Divochiy, A.; Korneev, A.; Seleznev, V.; Kaurova, N.; Minaeva, O.; Goltsman, G. url  doi
openurl 
  Title Superconducting parallel nanowire detector with photon number resolving functionality Type Journal Article
  Year 2009 Publication J. Modern Opt. Abbreviated Journal J. Modern Opt.  
  Volume 56 Issue 2-3 Pages 334-344  
  Keywords PNR; SSPD; SNSPD; thin superconducting films; photon number resolving detector; multiplication noise; telecom wavelength; NbN  
  Abstract We present a new photon number resolving detector (PNR), the Parallel Nanowire Detector (PND), which uses spatial multiplexing on a subwavelength scale to provide a single electrical output proportional to the photon number. The basic structure of the PND is the parallel connection of several NbN superconducting nanowires (100 nm-wide, few nm-thick), folded in a meander pattern. Electrical and optical equivalents of the device were developed in order to gain insight on its working principle. PNDs were fabricated on 3-4 nm thick NbN films grown on sapphire (substrate temperature TS=900C) or MgO (TS=400C) substrates by reactive magnetron sputtering in an Ar/N2 gas mixture. The device performance was characterized in terms of speed and sensitivity. The photoresponse shows a full width at half maximum (FWHM) as low as 660ps. PNDs showed counting performance at 80 MHz repetition rate. Building the histograms of the photoresponse peak, no multiplication noise buildup is observable and a one photon quantum efficiency can be estimated to be QE=3% (at 700 nm wavelength and 4.2 K temperature). The PND significantly outperforms existing PNR detectors in terms of simplicity, sensitivity, speed, and multiplication noise.  
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  Series Volume Series Issue Edition  
  ISSN 0950-0340 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number RPLAB @ gujma @ Serial 701  
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