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Now showing items 1-20 of 115

  • An acoustic double fishnet using Helmholtz resonators 

    Murray, Alasdair R.J.; Summers, I.R.; Sambles, J. Roy; Hibbins, Alastair P. (Acoustical Society of America, 2014)
    The acoustic transmission of a closely spaced pair of patterned and perforated rigid plates is explored in air. The structure resembles an acoustic double fishnet design, with each plate modified such that the gap between ...
  • Analysis of the sign-dependent switching observed in a hybrid aligned nematic cell 

    Cornford, Stephen Leslie; Taphouse, T. S.; Sambles, J. Roy (Institute of Physics and Deutsche Physikalische Gesellschaft, 2009)
    An optical waveguide experiment was used to study the influence of dc electric fields on a hybrid aligned nematic liquid crystal cell. This dc switching differed from ac switching in two ways: first, the equilibrium states ...
  • Angle-independent microwave absorption by ultrathin microcavity arrays 

    Brown, James R.; Hibbins, Alastair P.; Lockyear, Matthew J.; Lawrence, Christopher R.; Sambles, J. Roy (American Institute of Physics, 2008)
    The resonant absorption of microwave radiation by thin, two-dimensional microcavity arrays has been studied. Resonant modes associated with these structures, formed from copper-clad FR4 laminates, exhibit both an azimuthal ...
  • Babinet’s principle and the band structure of surface waves on patterned metal arrays 

    Edmunds, James D.; Taylor, Melita C.; Hibbins, Alastair P.; Sambles, J. Roy; Youngs, I.J. (American Institute of Physics, 2010)
    The microwave response of an array of square metal patches and its complementary structure, an array of square holes, has been experimentally studied. The resonant phenomena, which yield either enhanced transmission or ...
  • Backflow in the relaxation of a hybrid aligned nematic cell 

    Jewell, Sharon A.; Sambles, J. Roy (American Institute of Physics, 2003)
    The optical convergent-beam technique has been used to measure the changing director profile in a 4.6 µm ZLI-2293 filled hybrid aligned nematic cell when a 7 Vrms ac voltage was removed. The relaxation process has been ...
  • Broad-band polarization conversion from a finite periodic structure in the microwave regime 

    Hallam, B. T.; Lawrence, Christopher R.; Hooper, Ian R.; Sambles, J. Roy (American Institute of Physics, 2004)
    A reflection grating demonstrating extraordinarily broad-band polarization conversion in a nondiffractive regime has been studied at microwave frequencies. This single-element structure has been fabricated by electrolessly ...
  • Broadband and low loss high refractive index metamaterials in the microwave regime 

    Campbell, T.; Hibbins, Alastair P.; Sambles, J. Roy; Hooper, Ian R. (American Institute of Physics, 2013)
    A broadband, low-loss, isotropic, high refractive index metamaterial comprising an array of close-packed cubic elements of cross-linked square metal plates is demonstrated in the microwave regime. The structuring of the ...
  • Broadband impedance-matched electromagnetic structured ferrite composite in the megahertz range 

    Parke, L.; Youngs, I.J.; Hibbins, Alastair P.; Sambles, J. Roy (American Institute of Physics (AIP), 2014)
    A high refractive-index structured ferrite composite is designed to experimentally demonstrate broadband impedance matching to free-space. It consists of an array of ferrite cubes that are anisotropically spaced, thereby ...
  • Coexisting Nematic and Smectic- A Phases in a Twisted Liquid-Crystal Cell 

    Ruan, Lizhen; Osipov, M. A.; Sambles, J. Roy (American Physical Society, 2001)
    Twisted homogeneously planar-aligned nematic liquid-crystal cells are cooled into the smectic- A phase. The expected defective structure does not form. Instead the cells still show good optical-guiding characteristics. ...
  • Combined X-Ray and Fully Leaky Guided Mode Studies of the Smectic Layer and Optic Tensor Configuration in a Ferroelectric Liquid-Crystal Cell 

    Hodder, B.; Sambles, J. Roy; Jenkins, S.; Richardson, Robert M. (American Physical Society, 2000)
    X-ray scattering together with optical characterization using fully leaky guided modes have been used for the first time to study the same ferroelectric liquid-crystal cell. This enables direct calculation of an accurate ...
  • Conoscopic observation of director reorientation during Poiseuille flow of a nematic liquid crystal 

    Holmes, Christopher J.; Cornford, Stephen Leslie; Sambles, J. Roy (American Institute of Physics, 2009)
    Director reorientation under pressure driven (Poiseuille) flow is observed conoscopically for the liquid crystal 5CB aligned at an azimuthal angle of 45° to the direction of flow. A polyimide surface treatment (AL 1254) ...
  • Control of the stop band of an acoustic double fishnet 

    Murray, Alasdair R.J.; Hendry, Euan; Summers, I.R.; Sambles, J. Roy; Hibbins, Alastair P. (Journal of the Acoustical Society of America, 2013)
    The acoustic transmittance of two closely spaced solid plates, each perforated with a square array of cylindrical holes, exhibits a band of near-perfect acoustic attenuation originating from hybridization between a resonance ...
  • Coupled surface plasmon polaritons on thin metal slabs corrugated on both surfaces 

    Hooper, Ian R.; Sambles, J. Roy (American Physical Society, 2004)
    A modelling study of the effect of coupled surface plasmon polaritons (SPPs) on the optical response of a thin metal film corrugated on both surfaces is presented. Initially the case of conformally corrugated metal films ...
  • Coupled surface plasmons and optical guided wave exploration of near-surface director profile 

    Yang, Fuzi; Ruan, Lizhen; Jewell, Sharon A.; Sambles, J. Roy (Institute of Physics and Deutsche Physikalische Gesellschaft, 2007)
    For a liquid crystal (LC) cell with thin silver claddings it is possible, using a high index coupling prism, to excite both surface plasmon modes and ordinary optical guided modes. In a situation where the tilt of the ...
  • Coupled surface-plasmon-like modes between metamaterial 

    Hibbins, Alastair P.; Lockyear, Matthew J.; Sambles, J. Roy (American Physical Society, 2007)
    Perfectly conducting metals may be structured with holes to make metamaterials that support surface-plasmon-like modes at microwave frequencies. Results are presented for Fabry-Pérot-like standing wave resonances formed ...
  • The coupling of microwave radiation to surface plasmon polaritons and guided modes via dielectric gratings 

    Hibbins, Alastair P.; Sambles, J. Roy; Lawrence, Christopher R. (American Institute of Physics, 2000)
    It is shown that an absorbing dielectric layer, sinusoidally modulated in height, on top of a planar metal substrate, may be used to provide coupling between both s- and p-polarized incident microwave photons and surface ...
  • Coupling of near-grazing microwave photons to surface plasmon polaritons via a dielectric grating 

    Hibbins, Alastair P.; Sambles, J. Roy; Lawrence, Christopher R. (American Physical Society, 2000)
    A dielectric grating on top of a planar metal substrate is shown to couple near-grazing microwave photons to surface plasmon polaritons (SPPs). It is shown that when the grating grooves are oriented such that they are ...
  • Delay effect of switch-on in a supertwisted nematic cell 

    Yang, Fuzi; Dong, Youmei; Ruan, Lizhen; Sambles, J. Roy (American Institute of Physics, 2004)
    By using a convergent beam system and the fully leaky guided mode technique the switch-on dynamics of an 180° supertwisted nematic have been studied. Using the Ericksen–Leslie theory and analyzing the guided mode data taken ...
  • Determination of the director profile in a nematic cell from guided wave data: an inverse problem 

    Cornford, Stephen Leslie; Taphouse, T. S.; Newton, C. J. P.; Sambles, J. Roy (Institute of Physics and Deutsche Physikalische Gesellschaft, 2007)
    We consider an inverse problem: the estimation of the nematic director profile from experimental fully leaky guided mode data. This inverse problem is ill-posed in that small changes in the data may lead to large changes ...
  • Differential ellipsometric surface plasmon resonance sensors with liquid crystal polarization modulators 

    Hooper, Ian R.; Sambles, J. Roy (American Institute of Physics, 2004)
    Differential ellipsometric interrogation of surface plasmon (SP) resonances is a technique that gives ultrahigh sensitivity to refractive index changes, and it may provide the basis for chemical and biological sensors. In ...