Now showing items 62-81 of 136

  • 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 ...
  • 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. ...
  • 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 ...
  • 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 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 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 ...
  • Optical imaging of the effect of in-plane fields on cholesteric liquid crystals 

    Jewell, Sharon A.; Sambles, J. Roy (American Physical Society, 2008)
    The effects of in-plane electric fields on the director structure of cholesteric liquid crystals has been imaged in three dimensions using fluorescence confocal polarizing microscopy. The results show that a liquid crystal ...
  • Optical properties of a light-emitting polymer directly patterned by soft lithography 

    Lawrence, J. R.; Andrew, P.; Barnes, William L.; Buck, M.; Turnbull, G. A.; Samuel, I. D. W. (American Institute of Physics, 2002)
    We present the optical properties of a directly patterned light-emitting polymer. The patterned poly(2-methoxy-5-(3',7'-dimethyloctyloxy)-paraphenylenevinylene film is fabricated using hot embossing lithography. The effect ...
  • Optical resonances on sub-wavelength silver lamellar gratings 

    Gadsdon, Martyn Richard; Hooper, Ian R.; Sambles, J. Roy (Optical Society of America, 2008)
    The optical response of sub-wavelength silver lamellar gratings has been theoretically investigated. Two distinct types of resonance have been predicted for incident radiation with E-field perpendicular to the long axis ...
  • Optical waveguide characterization of a tristable antiferroelectric liquid crystal cell 

    Jewell, Sharon A.; Sambles, J. Roy; Goodby, J. W.; Hall, A. W.; Cowling, S. J. (American Institute of Physics, 2004)
    The optical convergent-beam waveguide technique has been used to characterize a homogeneously aligned 3 µm cell containing a liquid crystal in the antiferroelectric phase. The director structure has been quantified with ...
  • Optically guided mode study of nematic liquid crystal alignment on a zero-order grating 

    Hallam, B. T.; Sambles, J. Roy (American Physical Society, 2000)
    The characterization of a liquid crystal cell, which comprises one zero-order (that is, at the wavelength of study it is nondiffractive) diffraction grating and one rubbed polyimide-coated substrate, has been performed ...