Browsing by Author "Wang, Yi"

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    Dye-Assisted Gain of Strongly Confined Surface Plasmon Polaritons in Silver Nanowires
    (American Chemical Society, 2014) Paul, Aniruddha; Zhen, Yu-Rong; Wang, Yi; Chang, Wei-Shun; Xia, Younan; Nordlander, Peter; Link, Stephan; Laboratory for Nanophotonics
    Subwavelength confinement and active control of light is essential for nanoscale communication devices at visible frequencies that support large bandwidths.[1-5] Noble-metal nanostructures present an excellent platform for strongly confined optical waveguides [6-13] because of their ability to support surface plasmon polaritons (SPPs).[14] However, SPP propagation suffers from losses that seriously limit their application potential. [9] Although significant progress toward SPP loss compensation has been reported for various planar 2D waveguide structures,[15-20] as well as lasing involving strongly localized plasmon modes,[21,22] SPP gain in 1D nanoscale waveguides at visible frequencies is yet to be accomplished. Here, we report the first demonstration of gain for deep subwavelength confined SPPs (mode area = λ2/40) in chemically prepared silver nanowires (Ag NWs). We measured a gain coefficient of 270 cm-1 resulting in 14% loss compensation using a continuous-wave (cw) pump laser. These results are an important step toward total loss compensation for highly confined nanowire SPPs.
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    Genetic variation in anti-herbivore chemical defences in an invasive plant
    (British Ecological Society, 2012) Wang, Yi; Siemann, Evan; Wheeler, Gregory S.; Zhu, Lin; Gu, Xue; Ding, Jianqing
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    Wavelets in the solution of thermal radiative transfer equation
    (1998) Wang, Yi; Bayazitoglu, Yildiz
    The wavelet bases approximation idea which is first proposed by Daubechies is successfully introduced in both nongray and linear anisotropic scattering radiation fields. In nongray medium, wavelet bases are used in frequency domain in radiative transfer equation. Wavelet method allows the radiative problems to be calculated with fewer assumptions. Wavelet method also can be combined with arbitrary absorption coefficient model. Results by wavelet method compare well with box model absorption coefficient cases. Deviations are observed in situations in which the medium is optically thin. In scattering medium, wavelet bases are used in angular domain. Promising results are shown in linear anisotropic scattering cases. It also can be used with arbitrary scattering model.