Now showing items 135-154 of 469

  • Excitons and interband terahertz transitions in narrow-gap carbon nanotubes 

    Portnoi, M.E.; Downing, C.A.; Hartmann, Richard R.; Shelykh, I.A. (Institute of Electrical and Electronics Engineers (IEEE), 2013)
    We show, via a solution of the quasi-one-dimensional two-body problem applied to a Dirac system, that excitonic effects suppress the one-dimensional Van Hove singularity in single-walled carbon nanotubes with narrow band gaps.
  • Excitons in narrow-gap carbon nanotubes 

    Hartmann, Richard R.; Shelykh, I.A.; Portnoi, M.E. (American Physical Society, 2011)
    We calculate the exciton binding energy in single-walled carbon nanotubes with narrow band gaps, accounting for the quasirelativistic dispersion of electrons and holes. Exact analytical solutions of the quantum relativistic ...
  • Experimental method for reliably establishing the refractive index of buprestid beetle exocuticle 

    Noyes, Joseph Alexander; Vukusic, Peter; Hooper, Ian R. (Optical Society of America, 2007)
    In this study we apply an existing optical characterisation technique to establish reliably the complex refractive indices of layers comprising a natural multilayer reflector in the beetle Chrysochroa raja. Its reflector ...
  • Exploration of the surface director profile in a liquid crystal cell using coupling between the surface plasmon and half-leaky optical guided modes 

    Yang, Fuzi; Ruan, Lizhen; Sambles, J. Roy (American Institute of Physics, 2008)
    The half-leaky guided mode geometry with a thin metal tunnel barrier as one cladding layer is used to explore the distribution of the director very near to the surface in a hybrid aligning nematic liquid crystal cell. From ...
  • Ferrite-filled cavities for compact planar resonators 

    Keatley, Paul Steven; Durrant, C.J.; Berry, S.J.; Sirotkin, Evgeny; Hibbins, Alastair P.; Hicken, R.J. (American Institute of Physics (AIP) -, 2014)
    Sub-wavelength metallic planar cavities, closed at one end, have been constructed by wrapping aluminium foil around teflon or ferrite slabs. Finite cavity width perturbs the fundamental cavity mode frequency of ferrite-filled ...
  • Ferromagnetic microswimmers 

    Ogrin, Feodor Y.; Petrov, Peter G.; Winlove, C. Peter (American Physical Society, 2008)
    We propose a model for a novel artificial low Reynolds number swimmer, based on the magnetic interactions of a pair of ferromagnetic particles: one with hard and the other with soft magnetic properties, connected by a ...
  • Ferrous iron formation following the co-aggregation of ferric iron and the Alzheimer's disease peptide β-amyloid (1-42). 

    Everett, J.; Cespedes, E.; Shelford, L.R.; Exley, C.; Collingwood, J.F.; Dobson, J.; van der Laan, Gerrit; Jenkins, C.A.; Arenholz, E.; Telling, N.D. (Royal Scociety, 2014)
    For decades, a link between increased levels of iron and areas of Alzheimer's disease (AD) pathology has been recognized, including AD lesions comprised of the peptide β-amyloid (Aβ). Despite many observations of this ...
  • Fiber-optical analog of the event horizon 

    Philbin, Thomas G.; Kuklewicz, Chris; Robertson, Scott; Hill, Stephen; König, Friedrich; Leonhardt, Ulf (American Association for the Advancement of Science, 2008)
    The physics at the event horizon resembles the behavior of waves in moving media. Horizons are formed where the local speed of the medium exceeds the wave velocity. We used ultrashort pulses in microstructured optical ...
  • Finite conductance governs the resonance transmission of thin metal slits at microwave frequencies 

    Suckling, James R.; Hibbins, Alastair P.; Lockyear, Matthew J.; Preist, T. W.; Sambles, J. Roy; Lawrence, Christopher R. (American Physical Society, 2004)
    Fabry-Perot–like resonant transmission of microwave radiation through a single subwavelength slit in a thick aluminum plate is quantified for a range of slit widths. Surprisingly, and in contrast to previous studies [e.g., ...
  • Fitting the young main-sequence: distances, ages and age spreads 

    Mayne, Nathan J.; Naylor, Tim (Oxford University Press / Royal Astronomical Society, 2008)
    We use several main-sequence models to derive distances (and extinctions), with statistically meaningful uncertainties for 11 star-forming regions and young clusters. The model dependency is shown to be small, allowing us ...
  • Flat photonic bands in guided modes of textured metallic microcavities 

    Salt, M. G.; Barnes, William L. (American Physical Society, 2000)
    A detailed experimental study of how wavelength-scale periodic texture modifies the dispersion of the guided modes of λ/2 metal-clad microcavities is presented. We first examine the case of a solid-state microcavity textured ...
  • Flexural phonons in free-standing graphene 

    Mariani, Eros; von Oppen, Felix (American Physical Society, 2008)
    Rotation and reflection symmetries impose that out-of-plane (flexural) phonons of freestanding graphene membranes have a quadratic dispersion at long wavelength and can be excited by charge carriers in pairs only. As a ...
  • Flow-driven transition and associated velocity profiles in a nematic liquid-crystal cell 

    Jewell, Sharon A.; Cornford, Stephen Leslie; Yang, Fuzi; Cann, P. S.; Sambles, J. Roy (American Physical Society, 2009)
    The alignment properties and distribution of flow speed during Poiseuille flow through a microchannel of a nematic liquid crystal in a cell with homeotropic surface alignment has been measured using a combination of ...
  • Flow-Induced Twist-Compression in a Twisted Nematic Cell 

    Ruan, Lizhen; Sambles, J. Roy (American Physical Society, 2003)
    An optical convergent-beam guided-wave technique is used to explore in detail the dynamic flow effects in a twisted nematic cell. During switch-on it is found that the dynamic flow compresses the director twist to regions ...
  • Fluorescence enhancement through modified dye molecule absorption associated with the localized surface plasmon resonances of metallic dimers 

    Zoriniants, George; Barnes, William L. (Institute of Physics and Deutsche Physikalische Gesellschaft, 2008)
    Nano-antennae consisting of gold particle dimers were fabricated by electron-beam lithography. Dark-field scattering spectroscopy was used to probe the plasmonic response of individual nano-antennae and to characterize the ...
  • Fluorescent dyes as a probe for the localized field of coupled surface plasmon-related resonances 

    Kreiter, M.; Neumann, T.; Mittler, S.; Knoll, W.; Sambles, J. Roy (American Physical Society, 2001)
    The fluorescence light of Cy5 dye molecules in the vicinity of a metal grating is studied for varying directions of both the exciting and the emitted light. A different angular dependence of the intensity of the emitted ...
  • Franck-Condon blockade in suspended carbon nanotube quantum dots 

    Leturcq, Renaud; Stampfer, Christoph; Inderbitzin, Kevin; Durrer, Lukas; Hierold, Christofer; Mariani, Eros; Schultz, Maximilian G.; von Oppen, Felix; Ensslin, Klaus (Nature Publishing Group, 2009)
    Understanding the influence of vibrational motion of the atoms on electronic transitions in molecules constitutes a cornerstone of quantum physics, as epitomized by the Franck-Condon principle of spectroscopy. Recent ...
  • The fresnel interferometric imager 

    Koechlin, Laurent; Serre, Denis; Deba, Paul; Pello, Roser; Peillon, Christelle; Duchon, Paul; Gomez de Castro, Ana Ines; Karovska, Margarita; Desert, J.-M.; Ehrenreich, D.; Hebrard, G.; Lecavelier des Etangs, A.; Ferlet, R.; Sing, David K.; Vidal-Madjar, A. (Springer Verlag, 2009)
    The Fresnel Interferometric Imager has been proposed to the European Space Agency (ESA) Cosmic Vision plan as a class L mission. This mission addresses several themes of the CV Plan: Exoplanet study, Matter in extreme ...
  • A gamma-ray burst at a redshift of z approximate to 8.2 

    Tanvir, N.R.; Fox, D.B.; Levan, A.J.; Berger, E.; Wiersema, K.; Fynbo, J.P.U.; Cucchiara, A.; Kruehler, T.; Gehrels, N.; Bloom, J.S.; Greiner, J.; Evans, P.A.; Rol, E.; Olivares, F.; Hjorth, J.; Jakobsson, P.; Farihi, J.; Willingale, R.; Starling, R.L.C.; Cenko, S.B.; Perley, D.; Maund, J.R.; Duke, J.; Wijers, R.A.M.J.; Adamson, A.J.; Allan, A.; Bremer, M.N.; Burrows, D.N.; Castro-Tirado, A.J.; Cavanagh, B.; de Ugarte Postigo, A.; Dopita, M.A.; Fatkhullin, T.A.; Fruchter, A.S.; Foley, R.J.; Gorosabel, J.; Kennea, J.; Kerr, T.; Klose, S.; Krimm, H.A.; Komarova, V.N.; Kulkarni, S.R.; Moskvitin, A.S.; Mundell, C.G.; Naylor, Tim; Page, K.; Penprase, B.E.; Perri, M.; Podsiadlowski, P.; Roth, K.; Rutledge, R.E.; Sakamoto, T.; Schady, P.; Schmidt, B.P.; Soderberg, A.M.; Sollerman, J.; Stephens, A.W.; Stratta, G.; Ukwatta, T.N.; Watson, D.; Westra, E.; Wold, T.; Wolf, C. (Nature Publishing Group, 2009)
  • Gas accretion on to planetary cores: Three-dimensional self-gravitating radiation hydrodynamical calculations 

    Ayliffe, Benjamin A.; Bate, Matthew R. (Oxford University Press / Royal Astronomical Society, 2009)
    We present results from three-dimensional, self-gravitating radiation hydrodynamical models of gas accretion by planetary cores. In some cases, the accretion flow is resolved down to the surface of the solid core – the ...