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Now showing items 51-70 of 136

  • High-frequency dielectric relaxation of liquid crystals: THz time-domain spectroscopy of liquid crystal colloids 

    Oh-e, Masahito; Yokoyama, Hiroshi; Koeberg, Mattijs; Hendry, Euan; Bonn, Mischa (Optical Society of America, 2006)
    Terahertz time-domain spectroscopy has been used to study the dielectric relaxation of pure 4’–n-pentyl–4–cyanobiphenyl (5CB) liquid crystal (LC) and its mixtures with 10 µm SiO2 particles in the frequency range 0.2–2 THz. ...
  • Importance of diffraction in determining the dispersion of designer surface plasmons 

    Hendry, Euan; Hibbins, Alastair P.; Sambles, J. Roy (American Physical Society, 2008)
    By employing a modified modal matching approach, we obtain explicit analytical expressions relating frequency to in-plane wave vector for the surface electromagnetic mode confined at the interface between vacuum and a ...
  • Interchain effects in the ultrafast photophysics of a semiconducting polymer: THz time-domain spectroscopy of thin films and isolated chains in solution 

    Hendry, Euan; Koeberg, Mattijs; Schins, Juleon M.; Nienhuys, H. K.; Sundström, V.; Siebbeles, L. D. A.; Bonn, Mischa (American Physical Society, 2005)
    We compare the generation and decay dynamics of charges and excitons in a model polymer semiconductor (MEH-PPV) in solution and drop-cast thin films, by recording the sub-ps transient complex conductivity using THz time-domain ...
  • Leaky-wave exploration of two-stage switch-on in a nematic pi-cell 

    Ruan, Lizhen; Sambles, J. Roy (American Institute of Physics, 2005)
    The two-stage switch-on dynamics of a nematic pi-cell are explored in detail using a convergent beam fully-leaky guided mode technique. The cell shows an initial switch-on with a time scale in the range several ms to tens ...
  • Light circulation and weaving in periodically patterned structures 

    Crouse, David; Jaquay, Eric; Maikal, Abdur; Hibbins, Alastair P. (American Physical Society, 2008)
    The circulation and weaving of light in one-dimensionally periodic structures as a result of the excitation of phase resonances are described. It is shown that phase resonances occur for s-polarized incident light with ...
  • Light emission through a corrugated metal film: The role of cross-coupled surface plasmon polaritons 

    Wedge, S.; Hooper, Ian R.; Sage, I.; Barnes, William L. (American Physical Society, 2004)
    We examine the phenomenon of light emission through a thin metal film that takes place via surface plasmon polaritons. Surface plasmon polariton cross coupling has recently been invoked to explain sharp features observed ...
  • Light outcoupling efficiency of top-emitting organic light-emitting diodes 

    Smith, L. H.; Wasey, J. A. E.; Barnes, William L. (American Institute of Physics, 2004)
    We report results obtained from modeling the light outcoupling efficiency of top–emitting organic light-emitting diode (OLED) structures and compare them with results from conventional substrate-emitting structures. We ...
  • Localized surface-plasmon resonances in periodic nondiffracting metallic nanoparticle and nanohole arrays 

    Parsons, J.; Hendry, Euan; Burrows, Christopher P.; Auguié, Baptiste; Sambles, J. Roy; Barnes, William L. (American Physical Society, 2009)
    We compare the optical response of periodic nondiffracting metallic nanoparticle and nanohole arrays. Experimental data from both structures show a pronounced minimum in their wavelength-dependent transmittance that, through ...
  • Low angular-dispersion microwave absorption of a dual-pitch nondiffracting metal bigrating 

    Lockyear, Matthew J.; Hibbins, Alastair P.; Sambles, J. Roy; Lawrence, Christopher R. (American Institute of Physics, 2003)
    The surface plasmon modes supported by a nondiffracting 90° bigrating consisting of three grooves per repeat period with one slightly shallower than the other two are characterized by studying the reflectivity from the ...
  • Low angular-dispersion microwave absorption of a metal dual-period nondiffracting hexagonal grating 

    Lockyear, Matthew J.; Hibbins, Alastair P.; Sambles, J. Roy; Lawrence, Christopher R. (American Institute of Physics, 2005)
    The microwave (11.3<λ0<16.7 mm) reflectivity response of a nondiffracting dual-period hexagonal grating is explored. In three directions at 60° to each other, the aluminum grating has a repeat period of 7.2 mm in which ...
  • Low threshold edge emitting polymer distributed feedback laser based on a square lattice 

    Vasdekis, A. E.; Turnbull, G. A.; Samuel, I. D. W.; Andrew, P.; Barnes, William L. (American Institute of Physics, 2005)
    We report the demonstration of a low-threshold, edge-emitting polymer distributed feedback laser based on a square lattice. The lattice constant was 268 nm, which corresponds to a lattice line spacing in the ΓM symmetry ...
  • Making Tunnel Barriers (Including Metals) Transparent 

    Hooper, Ian R.; Preist, T. W.; Sambles, J. Roy (American Physical Society, 2006)
    The classical "brick wall," which may, according to quantum mechanics, leak via tunneling, is here shown to be completely transparent when appropriate impedance matching media are placed both in front of and behind the ...
  • Measuring and modelling optical scattering and the colour quality of white pierid butterfly scales 

    Luke, S. M.; Vukusic, Peter; Hallam, B. T. (Optical Society of America, 2009)
    Colouration in butterfly wings is due to the interaction of light with a covering of scales on both wing surfaces. A combination of nanostructure in the scales, which reflect or scatter light, and absorption from chemical ...
  • Microwave liquid-crystal variable phase grating 

    Yang, Fuzi; Sambles, J. Roy (American Institute of Physics, 2004)
    A voltage-controlled variable phase grating, at microwave frequencies, is described and its response characterized. It comprises a stack of 71 aluminium strips of 1 mm thickness separated by 75 µm spaces, filled with ...
  • Microwave surface-plasmon-like modes on thin metamaterials 

    Lockyear, Matthew J.; Hibbins, Alastair P.; Sambles, J. Roy (American Physical Society, 2009)
    It has recently been shown that the structured surface of a perfect conductor can support surface-plasmon-like modes [Pendry et al., Science 305, 847 (2004)]. Such structures have a thickness of at least the order of the ...
  • Microwave transmission of a compound metal grating 

    Hibbins, Alastair P.; Hooper, Ian R.; Lockyear, Matthew J.; Sambles, J. Roy (American Physical Society, 2006)
    An array of subwavelength slits in a metallic substrate supports a series of Fabry-Perot-like resonances, where each harmonic results in a transmission peak. Addition of extra slits per period yields a compound grating ...
  • Microwave transmission through a single subwavelength annular aperture in a metal plate 

    Lockyear, Matthew J.; Hibbins, Alastair P.; Sambles, J. Roy; Lawrence, Christopher R. (American Physical Society, 2005)
    The resonant transmission of a small annular aperture, with a diameter much smaller than the radiation wavelength, in a thin metal plate is studied at microwave frequencies. It transpires that such an annular aperture ...
  • Microwave transmissivity of a metamaterial–dielectric stack 

    Butler, Celia A.M.; Parsons, James; Sambles, J. Roy; Hibbins, Alastair P.; Hobson, Peter A. (American Institute of Physics, 2009)
    A metamaterial layer comprising of a conducting square mesh surrounding subwavelength holes has a largely pure imaginary effective refractive index. We explore the microwave transmissivity of a stack of such metamaterial ...
  • Microwaves: thin metal slits and liquid crystals 

    Sambles, J. Roy; Hibbins, Alastair P.; Kelly, Robert J.; Suckling, James R.; Yang, Fuzi (SPIE, 2004)
    Using liquid crystals to control the propagation of microwaves is a potentially interesting technology. By incorporating small amounts of liquid crystal in thin slat metal structures through which the microwaves may ...
  • Molecular fluorescence above metallic gratings 

    Andrew, P.; Barnes, William L. (American Physical Society, 2001)
    We present measurements of the fluorescence of emitters located in close proximity (d<λ) to metallic grating surfaces. By measuring both the spontaneous emission lifetime and angle-dependent radiation pattern of a monolayer ...