Now showing items 261-280 of 479

  • Observation of backflow in the switch-on dynamics of a hybrid aligned nematic 

    Jewell, Sharon A.; Sambles, J. Roy (American Institute of Physics, 2004)
    The optical convergent-beam technique is used to measure, in 0.3 ms steps, the response of the director in a 4.6-µm-thick ZLI-2293 filled hybrid aligned nematic cell when a 10 kHz, 7 Vrms ac voltage is applied to the cell. ...
  • Observation of ferromagnetic resonance in the time domain 

    Hicken, R.J.; Wu, J. (American Institute of Physics, 1999)
    Optical pump–probe spectroscopy has been used to observe damped ferromagnetic resonance (FMR) oscillations in thin film Fe samples. The FMR was pumped by magnetic field pulses generated by an optically triggered photoconductive ...
  • Observation of negative-frequency waves in a water tank: A classical analogue to the Hawking effect? 

    Rousseaux, Germain; Mathis, Christian; Maissa, Philippe; Philbin, Thomas G.; Leonhardt, Ulf (Institute of Physics, 2008)
    The conversion of positive-frequency waves into negative-frequency waves at the event horizon is the mechanism at the heart of the Hawking radiation of black holes. In black-hole analogues, horizons are formed for waves ...
  • Observation of T2-like coherent optical phonons in epitaxial Ge2Sb2Te5/GaSb(001) films 

    Shalini, Ashawaraya; Liu, Y.; Al-Jarah, Uday Ali Sabeeh; Srivastava, G.P.; Wright, C. David; Katmis, F.; Braun, W.; Hicken, R.J. (Nature Publishing Group, 2013)
    The phonon spectrum of Ge2Sb2Te5 is a signature of its crystallographic structure and underlies the phase transition process used in memory applications. Epitaxial materials allow coherent optical phonons to be studied in ...
  • Observation of the full 12-hour-long transit of the exoplanet HD80606b: Warm-Spitzer photometry and SOPHIE spectroscopy 

    Hebrard, G.; Desert, J.-M.; Diaz, R.F.; Boisse, I.; Bouchy, F.; Lecavelier des Etangs, A.; Moutou, C.; Ehrenreich, D.; Arnold, L.; Bonfils, X.; Delfosse, X.; Desort, M.; Eggenberger, A.; Forveille, T.; Gregorio, J.; Lagrange, A.-M.; Lovis, C.; Pepe, F.; Perrier, C.; Pont, F.; Queloz, D.; Santerne, A.; Santos, N.C.; Segransan, D.; Sing, David K.; Udry, S.; Vidal-Madjar, A. (EDP Sciences for European Southern Observatory (ESO), 2010)
    We present new observations of a transit of the 111.4-day-period exoplanet HD 80606b. Due to this long orbital period and to the orientation of the eccentric orbit (e = 0.9), HD 80606b's transits last for about 12 hours. ...
  • Observation of thickness dependence of magnetic surface anisotropy in ultrathin amorphous films. 

    Hicken, R.J.; Rado, G.T.; Xiao, G.; Chien, C.L. (American Physical Society, 1990)
    Ferromagnetic resonance (FMR) and SQUID magnetometry measurements have been made on multilayers of amorphous Fe70B30/Ag. The dependence of the magnetic surface anisotropy constant Ks on the magnetic layer thickness 2L has ...
  • Observed luminosity spread in young clusters and Fu Ori stars: a unified picture 

    Baraffe, I.; Vorobyov, Eduard I.; Chabrier, G. (American Astronomical Society, 2012)
    The idea that non-steady accretion during the embedded phase of protostar evolution can produce the observed luminosity spread in the Herzsprung–Russell diagram (HRD) of young clusters has recently been called into question. ...
  • On the creation of future probabilistic design weather years from UKCP09 

    Eames, Matthew E.; Kershaw, Tristan; Coley, David (SAGE Publications, 2011)
    Weather data are used extensively by building scientists and engineers to study the performance of their designs, help compare design alternatives and ensure compliance with building regulations. Given a changing climate, ...
  • On the effects of clouds and hazes in the atmospheres of hot Jupiters: semi-analytical temperature-pressure profiles 

    Heng, Kevin; Hayek, W.; Pont, F.; Sing, David K. (Oxford University Press on behalf of the Royal Astronomical Society, 2011)
    Motivated by the work of Guillot, we present a semi-analytical formalism for calculating the temperature–pressure profiles in hot Jovian atmospheres which includes the effects of clouds/hazes and collision-induced absorption. ...
  • On the mechanism of charge transport in pentacene 

    van Laarhoven, Hendrik A.; Flipse, Cees F. J.; Koeberg, Mattijs; Bonn, Mischa; Hendry, Euan; Orlandi, G.; Jurchescu, O. D.; Palstra, T. T. M.; Troisi, A. (American Institute of Physics, 2008)
    Terahertz transient conductivity measurements are performed on pentacene single crystals, which directly demonstrate a strong coupling of charge carriers to low frequency molecular motions with energies centered around 1.1 ...
  • On the Nature of the Herbig B[e] Star Binary System V921 Scorpii: Discovery of a Close Companion and Relation to the Large-scale Bipolar Nebula 

    Kraus, Stefan; Calvet, Nuria; Hartmann, Lee; Hofmann, Karl-Heinz; Kreplin, Alexander; Monnier, John D.; Weigelt, Gerd (IOP Publishing for American Astronomical Society, 2012)
    Belonging to the group of B[e] stars, V921 Scorpii is associated with a strong infrared excess and permitted and forbidden line emission, indicating the presence of low- and high-density circumstellar gas and dust. Many ...
  • On the Nature of the Herbig B[e] Star Binary System V921 Scorpii: Geometry and Kinematics of the Circumprimary Disk on Sub-AU Scales 

    Kraus, Stefan; Calvet, Nuria; Hartmann, Lee; Hofmann, Karl-Heinz; Kreplin, Alexander; Monnier, John D.; Weigelt, Gerd (IOP Publishing for American Astronomical Society, 2012)
    V921 Scorpii is a close binary system (separation 0farcs025) showing the B[e]-phenomenon. The system is surrounded by an enigmatic bipolar nebula, which might have been shaped by episodic mass-loss events, possibly triggered ...
  • One-dimensional Coulomb problem in Dirac materials 

    Downing, C.A.; Portnoi, M.E. (American Physical Society, 2014)
    We investigate the one-dimensional Coulomb potential with application to a class of quasirelativistic systems, so-called Dirac-Weyl materials, described by matrix Hamiltonians. We obtain the exact solution of the shifted ...
  • One-dimensional Van Hove polaritons 

    Arnardottir, K.B.; Kyriienko, O.; Portnoi, M.E.; Shelykh, I.A. (American Physical Society, 2013)
    We study the light-matter coupling of microcavity photons and an interband transition in a one-dimensional (1D) nanowire. Due to the Van Hove singularity in the density of states, resulting in a resonant character of the ...
  • One-way diffraction grating 

    Lockyear, Matthew J.; Hibbins, Alastair P.; White, Kevin R.; Sambles, J. Roy (American Physical Society, 2006)
    Diffraction gratings are elementary tools for much of optics and spectroscopy. Here, at microwave frequencies, we provide a new perspective on these fundamental structures. A transmission diffraction grating is presented ...
  • Operating characteristics of a semiconducting polymer laser pumped by a microchip laser 

    Turnbull, G. A.; Andrew, P.; Barnes, William L.; Samuel, I. D. W. (American Institute of Physics, 2003)
    We report the demonstration of a compact, all-solid-state polymer laser system featuring a microchip laser as the pump source. The laser was configured as a surface-emitting, two-dimensional distributed feedback laser, ...
  • Optical angular momentum in dispersive media 

    Philbin, Thomas G.; Allanson, O. (American Physical Society, 2012)
    The angular momentum density and flux of light in a dispersive, rotationally symmetric medium are derived from Noether's theorem. Optical angular momentum in a dispersive medium has no simple relation to optical linear ...
  • Optical Control over Surface-Plasmon-Polariton-Assisted THz Transmission through a Slit Aperture 

    Hendry, Euan; Garcia-Vidal, F. J.; Martin-Moreno, L.; Gómez Rivas, J.; Bonn, Mischa; Hibbins, Alastair P.; Lockyear, Matthew J. (American Physical Society, 2008)
    We demonstrate optical control over the transmission of terahertz (THz) radiation through a single subwavelength slit in an otherwise opaque silicon wafer. The addition of periodic corrugation on each side of the wafer ...
  • Optical control over transmission of terahertz radiation through arrays of subwavelength holes of varying size 

    Isaac, Thomas Henry; Gómez Rivas, J.; Hendry, Euan (American Physical Society, 2009)
    We modulate the transmission of terahertz (THz) radiation through periodic arrays of subwavelength holes in a metallic film by using pulses of visible-wavelength light to photoexcite the semiconducting substrate of the ...
  • Optical determination of flexoelectric coefficients and surface polarization in a hybrid aligned nematic cell 

    Mazzulla, A.; Ciuchi, F.; Sambles, J. Roy (American Physical Society, 2001)
    We present an optical study of the influence of both the flexoelectric effect and surface polarization on a hybrid-aligned nematic cell using the half-leaky guided mode technique. Tilt angle profiles, obtained from fits ...