Now showing items 69-88 of 136

  • 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 ...
  • ORE demo 

    Alastair, Hibbins (Uni of Exeter, 2013-10-04)
    An abstract
  • Orientational transition in a nematic liquid crystal at a patterned surface 

    Atherton, T. J.; Sambles, J. Roy (American Physical Society, 2006)
    We consider a semi-infinite nematic in contact with a periodic patterned surface with alternate planar and homeotropic stripes. Extending the work of Barbero et al., we find the free energy (assuming K1=K3) for the situations ...
  • Otto-coupled surface plasmons in a liquid crystal cell 

    Ruan, Lizhen; Yang, Fuzi; Sambles, J. Roy (American Institute of Physics, 2009)
    Surface plasmons on silver in the visible domain are excited using a several micron thick layer of liquid crystal as the optical tunnel barrier. This thickness is possible when the orientation of the director in the liquid ...
  • Phase resonances on metal gratings of identical, equally spaced alternately tapered slits 

    Rance, Helen J.; Hamilton, Oliver K.; Sambles, J. Roy; Hibbins, Alastair P. (American Institute of Physics, 2009)
    Phase resonances are observed in the microwave response of metal transmission gratings comprised of identical but alternately orientated tapered slits. Despite each slit having identical dimensions, and being equally spaced ...
  • Photonic band structure and emission characteristics of a metal-backed polymeric distributed feedback laser 

    Andrew, P.; Turnbull, G. A.; Samuel, I. D. W.; Barnes, William L. (American Institute of Physics, 2002)
    Optical losses associated with the metallic contacts necessary for charge injection are an obstacle to the development of an electrically pumped polymer laser. We show that it may be possible to overcome these losses by ...
  • Photonic bandgaps for grating-coupled waveguide modes with a silver tunnel barrier 

    Chen, Z.; Hooper, Ian R.; Sambles, J. Roy (Institute of Physics and Deutsche Physikalische Gesellschaft, 2007)
    The optical properties of a periodically modulated photoresist waveguide structure has been explored using the Kretschmann–Raether configuration with a thin silver tunnel barrier. A detailed experimental study of how ...
  • Photonic mode dispersion of a two-dimensional distributed feedback polymer laser 

    Turnbull, G. A.; Andrew, P.; Barnes, William L.; Samuel, I. D. W. (American Physical Society, 2003)
    We present an analysis of the photonic mode dispersion of a two-dimensional (2D) distributed feedback polymer laser based on the conjugated polymer poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylene vinylene]. We use a ...