نتایج جستجو برای: forbidden photonic band
تعداد نتایج: 163847 فیلتر نتایج به سال:
In this paper, a photonic crystal waveguide with point defects and lattice constant perturbations of +5%, -5% are being investigated. Firstly waveguide structures with constant and specific parameters are being studied and photonic band gap diagrams for TE/TM modes are depicted; then pulse propagation in the frequencies available in the band gap are shown. After that, effects of parameters like...
in this article, we suggested a novel design of polarization splitter based on coupler waveguide on inp substrate at 1.55mm wavelength. photonic crystal structure is consisted of two dimensional (2d) air holes embedded in inp/ingaasp material with an effective refractive index of 3.2634 which is arranged in a hexagonal lattice. the photonic band gap (pbg) of this structure is determined using t...
In this paper, using plane ware expansion method the polarization-dependent band structures are investigated in two dimensional photonic crystal waveguide with a square lattice composed of GaAs elliptic elements in air background. Then, the changes of the band structure with changing ellipticity of the elliptic elements are discussed. It is observed that by increasing the ellipticity of element...
In this paper we studied the focusing effect of electromagnetic wave in the two-dimensional graded photonic crystal consisting of Silicon rods in the air background with gradually varying lattice constant. The results showed that graded photonic crystal can focus wide beams on a narrow area at frequencies near the lower edge of the band gap, where equal frequency contours are not concave. For c...
In this work, using perturbation technique we have developed an approximate analytic model for evaluating the band structure of a 2-D octagonal photonic quasicrystal (PQC). Although numerical techniques are being used for evaluating such band structures, developing a numerical model to the best of our knowledge this work is the first instance of reporting helps to understand the physical proper...
Photonic crystal materials are based on a periodic modulation of the dielectric constant on length scales comparable to the wavelength of light. These materials can exhibit photonic band gaps; frequency regions for which the propagation of electromagnetic radiation is forbidden due to the depletion of the density of states. In order to exhibit a full band gap, 3D PCs must present a threshold re...
In this paper a new optical channel drop filter (CDF) based on two dimensional (2-D) photonic crystals (PhC) with hexagonal shaped structure is proposed and numerically demonstrated by using the finite-difference-time-domain (FDTD) and plane-wave-expansion (PWE) techniques. Photonic crystals (PhCs) are artificial dielectric nanostructure materials in which a periodic modulation of the material ...
In this article, by using the method of finite difference time domain (FDTD) and PML boundary conditions, we have studied the photonic band gaps for TE and TM modes in square and triangular lattices consisting of air holes in dielectric medium and compared the results. In addition, the effect of nonlinearity of the photonic crystal background on the photonic band gaps and comparison with the re...
In this study, a numerical investigation of photonic quasi-periodic Generalized Fibonacci (GF) (m, n) sequences is carried out in the visible spectrum. The transfer matrix method employed to study behavior wave propagation through structures. Firstly and highlight importance GF structure, its transmittance spectrum compared those periodic ordinary It shown that structure permits one obtain mult...
Photonic crystals with periodic arrangement of dielectric media can exhibit forbidden gaps in electromagnetic wave bands through Bragg diffraction (Ohtaka; 1979, Yablonovitch; 1987, John; 1987, Temelkuran; 2000). The prohibited frequency ranges are especially called photonic band gaps. If the periodicity is changed locally by introducing a defect, localized modes appear in the band gap (Ho; 199...
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