Now showing items 41-60 of 1854

    • Charged iodide in chains behind the highly efficient iodine doping in carbon nanotubes 

      Zubair, Ahmed; Tristant, Damien; Nie, Chunyang; Tsentalovich, Dmitri E.; Headrick, Robert J.; Pasquali, Matteo; Kono, Junichiro; Meunier, Vincent; Flahaut, Emmanuel; Monthioux, Marc; Gerber, Iann C.; Puech, Pascal (2017)
      The origin of highly efficient iodine doping of carbon nanotubes is not well understood. Relying on first-principles calculations, we found that iodine molecules (I2) in contact with a carbon nanotube interact to form ...
    • Some a posteriori error bounds for reduced-order modelling of (non-)parametrized linear systems 

      Feng, Lihong; Antoulas, Athanasios C.; Benner, Peter (2017)
      We propose a posteriori error bounds for reduced-order models of non-parametrized linear time invariant (LTI) systems and parametrized LTI systems. The error bounds estimate the errors of the transfer functions of the ...
    • Implicit vs. Explicit Approximate Matrix Inversion for Wideband Massive MU-MIMO Data Detection 

      Wu, Michael; Yin, Bei; Li, Kaipeng; Dick, Chris; Cavallaro, Joseph R.; Studer, Christoph (2017)
      Massive multi-user (MU) MIMO wireless technology promises improved spectral efficiency compared to that of traditional cellular systems. While data-detection algorithms that rely on linear equalization achieve near-optimal ...
    • Parallel Digital Predistortion Design on Mobile GPU and Embedded Multicore CPU for Mobile Transmitters 

      Li, Kaipeng; Ghazi, Amanullah; Tarver, Chance; Juntti, Markku; Boutellier, Jani; Abdelaziz, Mahmoud; Anttila, Lauri; Juntti, Markku; Valkama, Mikko; Cavallaro, Joseph R. (2017)
      Digital predistortion (DPD) is a widely adopted baseband processing technique in current radio transmitters. While DPD can effectively suppress unwanted spurious spectrum emissions stemming from imperfections of analog RF ...
    • Antenna-coupled light emission from two-dimensional materials 

      Bharadwaj, Palash; Parzefall, Markus; Jain, Achint; Novotny, Lukas (2017)
      We have studied the ultrafast conversion of electrons localized in vertical Au-hBN-Au tunnel junctions to free-space photons, mediated by resonant slot antennas. We achieve polarized, directional and resonantly enhanced ...
    • Repetitively Mode-Locked Cavity-Enhanced Absorption Spectroscopy (RML-CEAS) for Near-Infrared Gas Sensing 

      He, Qixin; Lou, Minhan; Zheng, Chuantao; Ye, Weilin; Wang, Yiding; Tittel, Frank K. (2017)
      A Pound-Drever-Hall (PDH)-based mode-locked cavity-enhanced sensor system was developed using a distributed feedback diode laser centered at 1.53 µm as the laser source. Laser temperature scanning, bias control of the ...
    • Broadband Absorption Engineering to Enhance Light Absorption in Monolayer MoS2 

      Bahauddin, Shah Mohammad; Robatjazi, Hossein; Thomann, Isabell (2016)
      Here we take a first step toward tackling the challenge of incomplete optical absorption in monolayers of transition metal dichalcogenides for conversion of photon energy, including solar, into other forms of energy. We ...
    • Compact TDLAS based sensor design using interband cascade lasers for mid-IR trace gas sensing 

      Dong, Lei; Tittel, Frank K.; Li, Chunguang; Sanchez, Nancy P.; Wu, Hongpeng; Zheng, Chuantao; Yu, Yajun; Sampaolo, Angelo; Griffin, Robert J. (2016)
      Two compact TDLAS sensor systems based on different structural optical cores were developed. The two optical cores combine two recent developments, gallium antimonide (GaSb)-based ICL and a compact multipass gas cell (MPGC) ...
    • High Chromaticity Aluminum Plasmonic Pixels for Active Liquid Crystal Displays 

      Olson, Jana; Manjavacas, Alejandro; Basu, Tiyash; Huang, Da; Schlather, Andrea E.; Zheng, Bob; Halas, Naomi; Nordlander, Peter; Link, Stephan (2016)
      Chromatic devices such as flat panel displays could, in principle, be substantially improved by incorporating aluminum plasmonic nanostructures instead of conventional chromophores that are susceptible to photobleaching. ...
    • Chiral and Achiral Nanodumbbell Dimers: The Effect of Geometry on Plasmonic Properties 

      Smith, Kyle W.; Zhao, Hangqi; Zhang, Hui; Sánchez -Iglesias, Ana; Grzelczak, Marek; Wang, Yumin; Chang, Wei-Shun; Nordlander, Peter; Liz-Marzán, Luis; Link, Stephan (2016)
      Metal nanoparticles with a dumbbell-like geometry have plasmonic properties similar to those of their nanorod counterparts, but the unique steric constraints induced by their enlarged tips result in distinct geometries ...
    • Generalized recovery algorithm for 3D super-resolution microscopy using rotating point spread functions 

      Shuang, Bo; Wang, Wenxiao; Shen, Hao; Tauzin, Lawrence J.; Flatebo, Charlotte; Chen, Jianbo; Moringo, Nicholas A.; Bishop, Logan D.C.; Kelly, Kevin F.; Landes, Christy F. (2016)
      Super-resolution microscopy with phase masks is a promising technique for 3D imaging and tracking. Due to the complexity of the resultant point spread functions, generalized recovery algorithms are still missing. We introduce ...
    • Mid-infrared dual-gas sensor for simultaneous detection of methane and ethane using a single continuous-wave interband cascade laser 

      Ye, Weilin; Li, Chunguang; Zheng, Chuantao; Sanchez, Nancy P.; Gluszek, Aleksander K.; Hudzikowski, Arkadiusz J.; Dong, Lei; Griffin, Robert J.; Tittel, Frank K. (2016)
      A continuous-wave (CW) interband cascade laser (ICL) based mid-infrared sensor system was demonstrated for simultaneous detection of atmospheric methane (CH4) and ethane (C2H6). A 3.337 µm CW ICL with an emitting wavenumber ...
    • Highly sensitive gas leak detector based on a quartz-enhanced photoacoustic SF6 sensor 

      Sampaolo, Angelo; Patimisco, Pietro; Giglio, Marilena; Chieco, Leonardo; Scamarcio, Gaetano; Tittel, Frank K.; Spagnolo, Vincenzo (2016)
      The implementation, performance validation, and testing of a gas-leak optical sensor based on mid-IR quartz-enhanced photoacoustic (QEPAS) spectroscopic technique is reported. A QEPAS sensor was integrated in a vacuum-sealed ...
    • Planar Laser-Based QEPAS Trace Gas Sensor 

      Ma, Yufei; He, Ying; Chen, Cheng; Yu, Xin; Zhang, Jingbo; Peng, Jiangbo; Sun, Rui; Tittel, Frank K. (2016)
      A novel quartz enhanced photoacoustic spectroscopy (QEPAS) trace gas detection scheme is reported in this paper. A cylindrical lens was employed for near-infrared laser focusing. The laser beam was shaped as a planar line ...
    • CW EC-QCL-based sensor for simultaneous detection of H2O, HDO, N2O and CH4ᅠusing multi-pass absorption spectroscopy 

      Yu, Yajun; Sanchez, Nancy P.; Griffin, Robert J.; Tittel, Frank K. (2016)
      A sensor system based on a continuous wave, external-cavity quantum-cascade laser (CW EC-QCL) was demonstrated for simultaneous detection of atmospheric H2O, HDO, N2O and CH4using a compact, dense pattern multi-pass gas ...
    • Performance Analysis and Optimization of a Hybrid Seismic Imaging Application 

      Paul, Sri Raj; Araya-Polo, Mauricio; Mellor-Crummey, John; Hohl, Detlef (2016)
      Applications to process seismic data are computationally expensive and, therefore, employ scalable parallel systems to produce timely results. Here we describe our experiences of using performance analysis tools to gain ...
    • Ultrathin AAO Membrane as a Generic Template for Sub-100 nm Nanostructure Fabrication 

      Robatjazi, Hossein; Bahauddin, Shah Mohammad; Macfarlan, Luke H.; Fu, Sidan; Thomann, Isabell (2016)
      Anodic aluminum oxide (AAO) templates are emerging as a platform for simple, cost-effective, high-throughput top-down nanofabrication of regular arrays of nanostructures. Thus far, however, AAO pattern transfer has largely ...
    • Magnetoreflection spectroscopy of monolayer transition-metal dichalcogenide semiconductors in pulsed magnetic fields 

      Stier, Andreas V.; McCreary, Kathleen M.; Jonker, Berend T.; Kono, Junichiro; Crooker, Scott A. (2016)
      The authors describe recent experimental efforts to perform polarization-resolved optical spectroscopy of monolayer transition-metal dichalcogenide semiconductors in very large pulsed magnetic fields to 65 T. The experimental ...
    • Improved Tuning Fork for Terahertz Quartz-Enhanced Photoacoustic Spectroscopy 

      Sampaolo, Angelo; Patimisco, Pietro; Giglio, Marilena; Vitiello, Miriam S.; Beere, Harvey E.; Ritchie, David A.; Scamarcio, Gaetano; Tittel, Frank K.; Spagnolo, Vincenzo (2016)
      We report on a quartz-enhanced photoacoustic (QEPAS) sensor for methanol (CH₃OH) detection employing a novel quartz tuning fork (QTF), specifically designed to enhance the QEPAS sensing performance in the terahertz (THz) ...
    • Carbon nanotube fiber terahertz polarizer 

      Zubair, Ahmed; Tsentalovich, Dmitri E.; Young, Colin C.; Heimbeck, Martin S.; Everitt, Henry O.; Pasquali, Matteo; Kono, Junichiro (2016)
      Conventional, commercially available terahertz (THz) polarizers are made of uniformly and precisely spaced metallic wires. They are fragile and expensive, with performance characteristics highly reliant on wire diameters ...