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  • Journal article
    Burn DM, Chadha M, Branford WR, 2015,

    Angular-dependent magnetization reversal processes in artificial spin ice

    , Physical Review B - Condensed Matter and Materials Physics, Vol: 92, ISSN: 1098-0121

    The angular dependence of the magnetization reversal in interconnected kagome artificial spin ice structures has been studied through experimental MOKE measurements and micromagnetic simulations. This reversal is mediated by the propagation of magnetic domain walls along the interconnecting bars, which either nucleate at the vertex or arrive following an interaction in a neighboring vertex. The physical differences in these processes show a distinct angular dependence allowing the different contributions to be identified. The configuration of the initial magnetization state, either locally or on a full sublattice of the system, controls the reversal characteristics of the array within a certain field window. This shows how the available magnetization reversal routes can be manipulated and the system can be trained.

  • Journal article
    Levy U, Berini P, Maier SA, Mortensen NAet al., 2015,

    Focus Issue on surface plasmon photonics introduction

    , OPTICS EXPRESS, Vol: 23, Pages: 32075-32079, ISSN: 1094-4087
  • Journal article
    Albella P, Shibanuma T, Maier S, 2015,

    Switchable directional scattering of electromagnetic radiation with subwavelength asymmetric silicon dimers

    , Scientific Reports, Vol: 5, ISSN: 2045-2322

    High refractive index dielectric nanoparticles show high promise as a complementary nanophotonics platform due to compared with plasmonic nanostructures low absorption losses and the co-existence of magnetic and electric resonances. Here we explore their use as resonantly enhanced directional scatterers.We theoretically demonstrate that an asymmetric dimer of silicon nanoparticles shows tuneable directional scattering depending on the frequency of excitation. This is due to the interference between dipoles excited in each nanoparticle, enabling directional control of the scattered light. Interestingly, this control can be achieved regardless of the polarization direction with respect to the dimer axis; however, difference in the polarization can shift the wavelengths at which the directional scattering is achieved. We also explore the application of such an asymmetric nanoantenna as a tuneable routing element in a nanometer scale a full numerical simulation, suggesting applications in optical nanocircuitry.

  • Journal article
    Pusch A, Oh S, Wuestner S, Roschuk T, De Luca A, Chen Y, Boual S, Ali Z, Phillips C, Hong M, Maier S, Udrea F, Hopper R, Hess Oet al., 2015,

    A highly efficient CMOS nanoplasmonic crystal enhanced slow-wave thermal emitter improves infrared gas-sensing devices

    , Scientific Reports, Vol: 5, ISSN: 2045-2322

    The application of plasmonics to thermal emitters is generally assisted by absorptive losses in the metal because Kirchhoff’s law prescribes that only good absorbers make good thermal emitters. Based on a designed plasmonic crystal and exploiting a slow-wave lattice resonance and spontaneous thermal plasmon emission, we engineer a tungsten-based thermal emitter, fabricated in an industrial CMOS process, and demonstrate its markedly improved practical use in a prototype non-dispersive infrared (NDIR) gas-sensing device. We show that the emission intensity of the thermal emitter at the CO2 absorption wavelength is enhanced almost 4-fold compared to a standard non-plasmonic emitter, which enables a proportionate increase in the signal-to-noise ratio of the CO2 gas sensor.

  • Journal article
    Wood JJ, Lafone L, Hamm JM, Hess O, Oulton RFet al., 2015,

    Plasmonic CROWs for Tunable Dispersion and High Quality Cavity Modes

    , Scientific Reports, Vol: 5, ISSN: 2045-2322

    Coupled resonator optical waveguides (CROWs) have the potential to revolutionise integrated optics, to slow-light and enhance linear and non-linear optical phenomena. Here we exploit the broad resonances and subwavelength nature of localized surface plasmons in a compact CROW design where plasmonic nanoparticles are side coupled to a dielectric waveguide. The plasmonic CROW features a low loss central mode with a highly tunable dispersion, that avoids coupling to the plasmonic nanoparticles close to the band-edge. We show that this low loss character is preserved in finite plasmonic CROWs giving rise to Fabry-Perot type resonances that have high quality factors of many thousands, limited only by the CROW length. Furthermore we demonstrate that the proposed CROW design is surprisingly robust to disorder. By varying the geometric parameters one can not only reduce the losses into dissipative or radiative channels but also control the outcoupling of energy to the waveguide. The ability to minimise loss in plasmonic CROWs while maintaining dispersion provides an effective cavity design for chip-integrated laser devices and applications in linear and non-linear nano-photonics.

  • Journal article
    Luo Y, Fernandez-Dominguez AI, Wiener A, Maier SA, Pendry JBet al., 2015,

    Reply to "Comment on “Surface Plasmons and Nonlocality: A Simple Model”

    , Physical Review Letters, Vol: 115, ISSN: 1079-7114
  • Journal article
    Moia D, Leijtens T, Noel N, Snaith HJ, Nelson J, Barnes PRFet al., 2015,

    Dye Monolayers Used as the Hole Transporting Medium in Dye-Sensitized Solar Cells

    , ADVANCED MATERIALS, Vol: 27, Pages: 5889-5894, ISSN: 0935-9648
  • Journal article
    Brivio F, Frost JM, Skelton JM, Jackson AJ, Weber OJ, Weller MT, Goni AR, Leguy AMA, Barnes PRF, Walsh Aet al., 2015,

    Lattice dynamics and vibrational spectra of the orthorhombic, tetragonal, and cubic phases of methylammonium lead iodide

    , PHYSICAL REVIEW B, Vol: 92, ISSN: 1098-0121
  • Journal article
    Leguy AMA, Azarhoosh P, Alonso MI, Campoy-Quiles M, Weber OJ, Yao J, Bryant D, Weller MT, Nelson J, Walsh A, van Schilfgaarde M, Barnes PRFet al., 2015,

    Experimental and theoretical optical properties of methylammonium lead halide perovskites

    , Nanoscale, Vol: 8, Pages: 6317-6327, ISSN: 2040-3372
  • Conference paper
    Alonso Alvarez D, Lackner D, Philipps SP, Bett AW, Ekins-Daukes NJet al., 2015,

    Photoluminescence-Based Current-Voltage Characterisation of Individual Subcells in Multi-Junction Devices

    , 31st European Photovoltaic Solar Energy Conference and Exhibition, Publisher: European Photovoltaic Solar Energy Conference and Exhibition, Pages: 1509-1513

    We demonstrate a photoluminescence based, contactless method to determine the current-voltage characteristics of the individual subcells in a multi-junction solar cell. The method, furthers known results for single junction devices and relies upon the reciprocity relation between the absorption and emission properties on a solar cell. Laser light with a suitable energy is used to excite carriers selectively in one junction and the internal voltages are deduced from the intensity of the resulting luminescence. The IV curves obtained this way on 1J, 2J and 6J devices are compared to those obtained using electroluminescence. Good agreement is obtained at high injection conditions while discrepancies at low injection are attributed to in-plane carrier transport.

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