Now showing items 129-148 of 459

  • Excitation and Imaging of Precessional Modes in Soft-Magnetic Squares 

    Neudert, A.; Keatley, Paul Steven; Kruglyak, V.V.; McCord, Jeffrey; Hicken, R.J. (Institute of Electrical and Electronics Engineers (IEEE), 2008)
    We investigated the high-frequency modes of 40 mum wide, 160 nm thick Fe 70Co8B12Si10 squares using time-resolved scanning Kerr microscopy. Two modes were identified using pulsed field excitation while the spatial character ...
  • Excitation of propagating spin waves with global uniform microwave fields 

    Au, Y.; Davison, T.; Ahmad, E.; Keatley, Paul Steven; Hicken, R.J.; Kruglyak, V.V. (American Institute of Physics, 2011)
    We demonstrate a magnonic architecture that converts global free-space uniform microwaves into spin waves propagating in a stripe magnonic waveguide. The architecture is based upon dispersion mismatch between the narrow ...
  • Excitation of remarkably nondispersive surface plasmons on a nondiffracting, dual-pitch metal grating 

    Hibbins, Alastair P.; Sambles, J. Roy; Lawrence, Christopher R. (American Institute of Physics, 2002)
    A nondiffracting metallic lamellar grating formed from three equally spaced grooves per repeat period, with one being slightly shallower than the other two is examined at microwave frequencies. When filled with a slightly ...
  • Exciton and electron-hole plasma formation dynamics in ZnO 

    Hendry, Euan; Koeberg, Mattijs; Bonn, Mischa (American Physical Society, 2007)
    We employ optical pump-THz probe measurements to study the formation of excitons and electron-hole plasmas following photogeneration of a hot electron-hole gas in the direct gap semiconductor zinc oxide. Below the Mott ...
  • Exciton storage in a nanoscale Aharonov-Bohm ring with electric field tuning 

    Fischer, Andrea M.; Campo, Vivaldo L.; Portnoi, M.E.; Römer, Rudolf A. (American Physical Society, 2009)
    We study analytically the optical properties of a simple model for an electron-hole pair on a ring subjected to perpendicular magnetic flux and in-plane electric field. We show how to tune this excitonic system from optically ...
  • 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 ...