14 research outputs found

    Two-dimensional Penrose-tiled photonic quasicrystals: diffraction of light and fractal density of modes

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    We report measurements of the diffraction pattern of a two-dimensional photonic quasicrystal structure. Using a set of plane waves defined by the diffraction pattern we introduce a theoretical approach for the calculation of the band structure which captures the rotational and inflational properties of the quasicrystal. Based on this model we find that the density of modes of the quasicrystal displays a fractal character and a depleted region analogous to the band gap in a periodic system

    The design of two-dimensional photonic quasicrystals by means of a Fourier transform method

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    We report a method of designing aperiodic photonic quasicrystals. The method is based on the recognition that the Fourier transform of the dielectric structure has a direct influence on the mode spectrum, and can be chosen to enhance the properties of the system. The diffraction of light by, and the band structure of, such modified photonic quasicrystals is investigated and compared to the properties of conventional photonic quasicrystals

    On the position of the digenean family Heronimidae: an inquiry into a cladistic classification of the Digenea

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    NUTRITION, GROWTH AND MORPHOGENESIS OF PLANT EMBRYOS

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