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Author Karpowicz, Nicholas; Lu, Xiaofei; Zhang, X.-C.
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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Call Number RPLAB @ gujma @ Serial 670
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Author Engel, Andreas; Aeschbacher, Adrian; Inderbitzin, Kevin; Schilling, Andreas; Il'in, Konstantin; Hofherr, Matthias; Siegel, Michael; Semenov, Alexei; Hübers, Heinz-Wilhelm
Title Tantalum nitride superconducting single-photon detectors with low cut-off energy Type Journal Article
Year 2011 Publication arXiv Abbreviated Journal arXiv
Volume Issue Pages 9
Keywords SSPD
Abstract Materials with a small superconducting energy gap favor a high detection efficiency of low-energy photons in superconducting nanowire single-photon detectors. We developed a TaN detector with smaller gap and lower density of states at the Fermi energy than in comparable NbN devices, while other relevant parameters remain essentially unchanged. This results in a reduction of the minimum photon energy required for direct detection to $\approx1/3$ as compared to NbN.
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Publisher Place of Publication arXiv:1110.4576 Editor
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Call Number RPLAB @ gujma @ Serial 687
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Author Poglitsch, A.; Waelkens, C.; Geis, N.; Feuchtgruber, H.; Vandenbussche, B.; Rodriguez, L.; Krause, O.; Renotte, E.; van Hoof, C.; Saraceno, P.; Cepa, J.; Kerschbaum, F.; Agnèse, P.; Ali, B.; Altieri, B.; Andreani, P.; Augueres, J.-L.; Balog, Z.; Barl, L.; Bauer, O. H.; Belbachir, N.; Benedettini, M.; Billot, N.; Boulade, O.; Bischof, H.; Blommaert, J.; Callut, E.; Cara, C.; Cerulli, R.; Cesarsky, D.; Contursi, A.; Creten, Y.; De Meester, W.; Doublier, V.; Doumayrou, E.; Duband, L.; Exter, K.; Genzel, R.; Gillis, J.-M.; Grözinger, U.; Henning, T.; Herreros, J.; Huygen, R.; Inguscio, M.; Jakob, G.; Jamar, C.; Jean, C.; de Jong, J.; Katterloher, R.; Kiss, C.; Klaas, U.; Lemke, D.; Lutz, D.; Madden, S.; Marquet, B.; Martignac, J.; Mazy, A.; Merken, P.; Montfort, F.; Morbidelli, L.; Müller, T.; Nielbock, M.; Okumura, K.; Orfei, R.; Ottensamer, R.; Pezzuto, S.; Popesso, P.; Putzeys, J.; Regibo, S.; Reveret, V.; Royer, P.; Sauvage, M.; Schreiber, J.; Stegmaier, J.; Schmitt, D.; Schubert, J.; Sturm, E.; Thiel, M.; Tofani, G.; Vavrek, R.; Wetzstein, M.; Wieprecht, E.; Wiezorrek, E.
Title The Photodetector Array Camera and Spectrometer (PACS) on the Herschel Space Observatory Type Journal Article
Year 2010 Publication Astron. Astrophys. Abbreviated Journal A&A
Volume 518 Issue Pages 12
Keywords PACS
Abstract The Photodetector Array Camera and Spectrometer (PACS) is one of the three science instruments on ESA's far infrared and submillimetre observatory. It employs two Ge:Ga photoconductor arrays (stressed and unstressed) with 16×25 pixels, each, and two filled silicon bolometer arrays with 16×32 and 32×64 pixels, respectively, to perform integral-field spectroscopy and imaging photometry in the 60-210 μm wavelength regime. In photometry mode, it simultaneously images two bands, 60-85 μm or 85-125 μm and 125-210 μm, over a field of view of ~1.75'× 3.5', with close to Nyquist beam sampling in each band. In spectroscopy mode, it images a field of 47” × 47”, resolved into 5×5 pixels, with an instantaneous spectral coverage of ~1500 km s-1 and a spectral resolution of ~175 km s-1. We summarise the design of the instrument, describe observing modes, calibration, and data analysis methods, and present our current assessment of the in-orbit performance of the instrument based on the performance verification tests. PACS is fully operational, and the achieved performance is close to or better than the pre-launch predictions.
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Call Number RPLAB @ gujma @ Serial 694
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Author Griffin, M. J.; Abergel, A.; Abreu, A.; Ade, P. A. R.; André, P.; Augueres, J.-L.; Babbedge, T.; Bae, Y.; Baillie, T.; Baluteau, J.-P.; Barlow, M. J.; Bendo, G.; Benielli, D.; Bock, J. J.; Bonhomme, P.; Brisbin, D.; Brockley-Blatt, C.; Caldwell, M.; Cara, C.; Castro-Rodriguez, N.; Cerulli, R.; Chanial, P.; Chen, S.; Clark, E.; Clements, D. L.; Clerc, L.; Coker, J.; Communal, D.; Conversi, L.; Cox, P.; Crumb, D.; Cunningham, C.; Daly, F.; Davis, G. R.; de Antoni, P.; Delderfield, J.; Devin, N.; di Giorgio, A.; Didschuns, I.; Dohlen, K.; Donati, M.; Dowell, A.; Dowell, C. D.; Duband, L.; Dumaye, L.; Emery, R. J.; Ferlet, M.; Ferrand, D.; Fontignie, J.; Fox, M.; Franceschini, A.; Frerking, M.; Fulton, T.; Garcia, J.; Gastaud, R.; Gear, W. K.; Glenn, J.; Goizel, A.; Griffin, D. K.; Grundy, T.; Guest, S.; Guillemet, L.; Hargrave, P. C.; Harwit, M.; Hastings, P.; Hatziminaoglou, E.; Herman, M.; Hinde, B.; Hristov, V.; Huang, M.; Imhof, P.; Isaak, K. J.; Israelsson, U.; Ivison, R. J.; Jennings, D.; Kiernan, B.; King, K. J.; Lange, A. E.; Latter, W.; Laurent, G.; Laurent, P.; Leeks, S. J.; Lellouch, E.; Levenson, L.; Li, B.; Li, J.; Lilienthal, J.; Lim, T.; Liu, S. J.; Lu, N.; Madden, S.; Mainetti, G.; Marliani, P.; McKay, D.; Mercier, K.; Molinari, S.; Morris, H.; Moseley, H.; Mulder, J.; Mur, M.; Naylor, D. A.; Nguyen, H.; O'Halloran, B.; Oliver, S.; Olofsson, G.; Olofsson, H.-G.; Orfei, R.; Page, M. J.; Pain, I.; Panuzzo, P.; Papageorgiou, A.; Parks, G.; Parr-Burman, P.; Pearce, A.; Pearson, C.; Pérez-Fournon, I.; Pinsard, F.; Pisano, G.; Podosek, J.; Pohlen, M.; Polehampton, E. T.; Pouliquen, D.; Rigopoulou, D.; Rizzo, D.; Roseboom, I. G.; Roussel, H.; Rowan-Robinson, M.; Rownd, B.; Saraceno, P.; Sauvage, M.; Savage, R.; Savini, G.; Sawyer, E.; Scharmberg, C.; Schmitt, D.; Schneider, N.; Schulz, B.; Schwartz, A.; Shafer, R.; Shupe, D. L.; Sibthorpe, B.; Sidher, S.; Smith, A.; Smith, A. J.; Smith, D.; Spencer, L.; Stobie, B.; Sudiwala, R.; Sukhatme, K.; Surace, C.; Stevens, J. A.; Swinyard, B. M.; Trichas, M.; Tourette, T.; Triou, H.; Tseng, S.; Tucker, C.; Turner, A.; Vaccari, M.; Valtchanov, I.; Vigroux, L.; Virique, E.; Voellmer, G.; Walker, H.; Ward, R.; Waskett, T.; Weilert, M.; Wesson, R.; White, G. J.; Whitehouse, N.; Wilson, C. D.; Winter, B.; Woodcraft, A. L.; Wright, G. S.; Xu, C. K.; Zavagno, A.; Zemcov, M.; Zhang, L.; Zonca, E.
Title The Herschel-SPIRE instrument and its in-flight performance Type Journal Article
Year 2010 Publication Astron. Astrophys. Abbreviated Journal A&A
Volume 518 Issue Pages 7
Keywords SPIRE
Abstract The Spectral and Photometric Imaging REceiver (SPIRE), is the Herschel Space Observatory`s submillimetre camera and spectrometer. It contains a three-band imaging photometer operating at 250, 350 and 500 μm, and an imaging Fourier-transform spectrometer (FTS) which covers simultaneously its whole operating range of 194-671 μm (447-1550 GHz). The SPIRE detectors are arrays of feedhorn-coupled bolometers cooled to 0.3 K. The photometer has a field of view of 4Â´× 8´, observed simultaneously in the three spectral bands. Its main operating mode is scan-mapping, whereby the field of view is scanned across the sky to achieve full spatial sampling and to cover large areas if desired. The spectrometer has an approximately circular field of view with a diameter of 2.6´. The spectral resolution can be adjusted between 1.2 and 25 GHz by changing the stroke length of the FTS scan mirror. Its main operating mode involves a fixed telescope pointing with multiple scans of the FTS mirror to acquire spectral data. For extended source measurements, multiple position offsets are implemented by means of an internal beam steering mirror to achieve the desired spatial sampling and by rastering of the telescope pointing to map areas larger than the field of view. The SPIRE instrument consists of a cold focal plane unit located inside the Herschel cryostat and warm electronics units, located on the spacecraft Service Module, for instrument control and data handling. Science data are transmitted to Earth with no on-board data compression, and processed by automatic pipelines to produce calibrated science products. The in-flight performance of the instrument matches or exceeds predictions based on pre-launch testing and modelling: the photometer sensitivity is comparable to or slightly better than estimated pre-launch, and the spectrometer sensitivity is also better by a factor of 1.5-2.
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Call Number RPLAB @ gujma @ Serial 695
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Author Lobanov, Y.V.; Tong, C.-Y.E.; Hedden, A.S.; Blundell, R.; Voronov, B.M.; Gol'tsman, G.N.
Title Direct measurement of the gain and noise bandwidths of HEB mixers Type Journal Article
Year 2011 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.
Volume 21 Issue 3 Pages 645-648
Keywords waveguide NbN HEB mixers
Abstract The intermediate frequency (IF) bandwidth of a hot electron bolometer (HEB) mixer is an important parameter of the mixer, in that it helps to determine its suitability for a given application. With the availability of wideband low noise amplifiers, it is simple to measure the performance of an HEB mixer over a wide range of IF at a fixed LO frequency using the standard Y-factor method. This in-situ method allows us to measure both the gain and noise bandwidths simultaneously. We have also measured mixer output impedance with a vector network analyser. Intrinsic time constant has been extracted from the impedance data and compared to the mixer's bandwidths determined from receiver Y-factor measurement.
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Call Number RPLAB @ gujma @ Serial 720
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Author Lobanov, Y. V.; Tong, Cheuk-Yu E.; Hedden, A. S.; Blundell, R.; Gol'tsman, G. N.
Title Microwave-assisted슠measurement슠of the슠frequency슠response슠of슠terahertz슠HEB슠mixers슠with a슠fourier슠transform슠spectrometer Type Conference Article
Year 2010 Publication 21st International Symposium on Space Terahertz Technology Abbreviated Journal 21st ISSTT
Volume Issue Pages 420-423
Keywords HEB mixer
Abstract We describe a novel method of operation of the HEB direct detector for use with a Fourier Transform Spectrometer. Instead of elevating the bath temperature, we have measured the RF response of waveguide HEB mixers by applying microwave radiation to select appropriate bias conditions. In our experiment, a microwave signal is injected into the HEB mixer via its IF port. By choosing an appropriate injection level, the device can be operated close to the desired operating point. Furthermore, we have shown that both thermal biasing and microwave injection can reproduce the same spectral response of the HEB mixer. However, with the use of microwave injection, there is no need to wait for the mixer to reach thermal equilibrium, so characterisation can be done in less time. Also, the liquid helium consumption for our wet cryostat is also reduced. We have demonstrated that the signalto-noise ratio of the FTS measurements can be improved with microwave injection.
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Call Number RPLAB @ gujma @ Serial 725
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Author Alda, Javier; Rico-García, José M.; López-Alonso, José M.; Boreman, G.
Title Optical antennas for nano-photonic applications Type Journal Article
Year 2005 Publication Nanotechnology Abbreviated Journal Nanotech.
Volume 16 Issue 5 Pages S230-S234
Keywords optical antennas
Abstract Antenna-coupled optical detectors, also named optical antennas, are being developed and proposed as alternative detection devices for the millimetre, infrared, and visible spectra. Optical and infrared antennas represent a class of optical components that couple electromagnetic radiation in the visible and infrared wavelengths in the same way as radioelectric antennas do at the corresponding wavelengths. The size of optical antennas is in the range of the detected wavelength and they involve fabrication techniques with nanoscale spatial resolution. Optical antennas have already proved and potential advantages in the detection of light showing polarization dependence, tuneability, and rapid time response. They also can be considered as point detectors and directionally sensitive elements. So far, these detectors have been thoroughly tested in the mid-infrared with some positive results in the visible. The measurement and characterization of optical antennas requires the use of an experimental set-up with nanometric resolution. On the other hand, a computation simulation of the interaction between the material structures and the incoming electromagnetic radiation is needed to explore alternative designs of practical devices.
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Call Number RPLAB @ gujma @ Serial 734
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Author Huang, Kevin C. Y.; Jun, Young Chul; Seo, Min-Kyo; Brongersma, Mark L.
Title Power flow from a dipole emitter near an optical antenna Type Journal Article
Year 2011 Publication Optics Express Abbreviated Journal Opt. Express
Volume 19 Issue 20 Pages 19084-19092
Keywords optical antennas
Abstract Current methods to calculate the emission enhancement of a quantum emitter coupled to an optical antenna of arbitrary geometry rely on analyzing the total Poynting vector power flow out of the emitter or the dyadic Green functions from full-field numerical simulations. Unfortunately, these methods do not provide information regarding the nature of the dominant energy decay pathways. We present a new approach that allows for a rigorous separation, quantification, and visualization of the emitter output power flow captured by an antenna and the subsequent reradiation power flow to the far field. Such analysis reveals unprecedented details of the emitter/antenna coupling mechanisms and thus opens up new design strategies for strongly interacting emitter/antenna systems used in sensing, active plasmonics and metamaterials, and quantum optics.
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Call Number RPLAB @ gujma @ Serial 743
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Author Kramer, B.; Chen, C-C.; Volakis, J.D.
Title The development of a mini-UWB antenna Type Journal Article
Year 2004 Publication Measurement and Techniques Association Symposium Abbreviated Journal AMTA
Volume Issue Pages 6
Keywords optical antennas; Ultra Wide Band; Spiral Antenna, Dielectric Loading
Abstract There is a great interest in the automotive and military sectors for small and broadband antennas that meet modern communication needs. These needs require ultra-wide bandwidth (>10:1) UWB antennas, such as the spiral antenna. However, the physical size at the low-frequency end typically becomes too large for practical applications. To reduce the size of the antenna, miniaturization techniques must be employed such as the use of high-contrast dielectric materials. Size reduction using high-contrast materials has been demonstrated for narrowband antennas, such as patch antennas, but not for broadband antennas to our knowledge. Therefore, the concept of miniaturizing a broadband spiral antenna using dielectric materials will be investigated experimentally and numerically.Issues that arise from dielectric loading such as impedance reduction will also be addressed. It will be shown using the results from these studies that there are practical limitations to the amount of miniaturization which can be achieved.
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Call Number RPLAB @ gujma @ Serial 751
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Author Knee, George C.; Simmons, Stephanie; Gauger, Erik M.; Morton, John J. L.; Riemann, Helge; Abrosimov, Nikolai V.; Becker, Peter; Pohl, Hans-Joachim; Itoh, Kohei M.; Thewalt, Mike L. W.; Briggs, G. Andrew D.; Benjamin, Simon C.
Title Violation of a Leggett–Garg inequality with ideal non-invasive measurements Type Journal Article
Year 2012 Publication Nature Communications Abbreviated Journal Nat. Comm.
Volume 3 Issue 606 Pages 6
Keywords fromIPMRAS
Abstract The quantum superposition principle states that an entity can exist in two different states simultaneously, counter to our 'classical' intuition. Is it possible to understand a given system's behaviour without such a concept? A test designed by Leggett and Garg can rule out this possibility. The test, originally intended for macroscopic objects, has been implemented in various systems. However to date no experiment has employed the 'ideal negative result' measurements that are required for the most robust test. Here we introduce a general protocol for these special measurements using an ancillary system, which acts as a local measuring device but which need not be perfectly prepared. We report an experimental realization using spin-bearing phosphorus impurities in silicon. The results demonstrate the necessity of a non-classical picture for this class of microscopic system. Our procedure can be applied to systems of any size, whether individually controlled or in a spatial ensemble.
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Call Number RPLAB @ gujma @ Serial 767
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