Browsing by Subject "Square-lattice"

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    Spatial filtering using dielectric photonic crystals at beam-type excitation
    (American Institute of Physics, 2010-12-06) Colak, E.; Cakmak, A. O.; Serebryannikov, A. E.; Özbay, Ekmel
    Spatial filtering is demonstrated at beam-type excitations by utilizing finite thickness slabs of two-dimensional dielectric photonic crystals (PCs) showing exotic Fabry-Perot resonances that are preserved over a wide range of variation of the incidence angle. Bandstop and dual-bandpass filtering effects are illustrated theoretically and the corresponding filters are validated in the microwave experiments by using square-lattice PCs. It is shown that the basic transmission features that were observed earlier for a plane-wave illumination are also recognizable at beam-type excitations. The proposed spatial filtering mechanism exhibits directional beaming. The desired widths and the locations of the passbands and stopbands are attainable in the angle domain with a proper choice of the operating frequency for the given excitation characteristics.
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    Wide-angle reflection-mode spatial filtering and splitting with photonic crystal gratings and single-layer rod gratings
    (Optical Society of American (OSA), 2014) Serebryannikov, A. E.; Lalanne, P.; Petrov, A. Y.; Özbay, Ekmel
    New diffractive optical elements offering a frequency tolerant, very efficient, high-pass and bandpass spatial filtering over a broad range of incidence angles are demonstrated by numerical simulations. The device operates in reflection mode owing to the (nearly) perfect blazing. It relies on two-dimensional square-lattice photonic crystals composed of dielectric rods with simple corrugations at the interface. Similar performance can be obtained with gratings composed of a single rod layer placed in the near field of a metal mirror, indicating a route to geometries that can be easily fabricated with modern nanotechnologies. Also equal splitting between zero and first negative orders can be obtained for incidence-angle variations that are wider than 60°. © 2014 Optical Society of America