Browsing by Subject "Photonic bands"

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    All-chalcogenide glass omnidirectional photonic band gap variable infrared filters
    (AIP Publishing, 2009) Kondakci, H. E.; Yaman, M.; Koylu, O.; Dana, A.; Bayındır, Mehmet
    We report on the design, fabrication, and characterization of spatially variable infrared photonic band gap filter that consists of thermally evaporated, high refractive indexcontrast, amorphous chalcogenide glass multilayers. Due to graded thickness structure, the filter exhibits a position dependent stop band and a cavity mode ranging from 1.8 to 3.4 μm3.4 μmwavelengths. Reflection measurements on the variable filter agree well with theoretical calculations. These results pave the way to low-loss infrared mirrors, filters, spectral imaging, and miniaturized spectrometers at infrared region.
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    Two-dimensional ferroelectric photonic crystals: Optics and band structure
    (Taylor & Francis Inc., 2013-09-20) Simsek S.; Mamedov, A. M.; Özbay, Ekmel
    In this report we present an investigation of the optical properties and band structure calculations for the photonic structures based on the functional materials- ferroelectrics. A theoretical approach to the optical properties of the 2D and 3D photonic crystals which yields further insight in the phenomenon of the reflection from different families of lattice planes in relation to the presence of photonic gaps or photonic bands. We calculate the photonic bands and optical properties of LiNbO3 based photonic crystals. Calculations of reflection and transmission spectra show the features correspond to the onset of diffraction, as well as to additional reflectance structures at large values of the angle of incidence. © 2013 Copyright Taylor and Francis Group, LLC.
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    Vortex lattice of a Bose-Einstein condensate as a photonic band gap material
    (IOP Institute of Physics Publishing, 2009) Taşgin, M. E.; Müstecaplioǧlu, Ö. E.; Oktel, M. Ö.
    Photonic crystal behavior of a rotating Bose-Einstein condensate with a triangular vortex lattice is reviewed and a scheme for getting much wider band gaps is proposed. It is shown that photonic band gaps can be widened an order of magnitude more by using a Raman scheme of index enhancement, in comparison to previously considered upper level microwave scheme.