Journal of Optoelectronical NanostructuresJournal of Optoelectronical Nanostructures
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Feed provided by Journal of Optoelectronical Nanostructures. Click to visit.First–Principle Calculation of the Electronic and Optical Properties of Nanolayered ZnO ...
http://jopn.miau.ac.ir/article_2570_357.html
First principle calculations of nanolayered ZnO polymorphs (Wurzite–, Zincblende–, Rocksalt–structures) in the scheme of density functional theory were performedwith the help of full potential linear augmented plane wave (FP-LAPW) method. Theexchange - correlation potential is described by generalized gradient approximation asproposed by Perdew–Burke–Ernzrhof (GGA–PBE) and modified Becke–Johnson (mBJ)approximation. The electronic behavior and the optical properties of the structures areinvestigated and compared to experimental data, where available. The electronic structureof w–ZnO and z–ZnO revealed a 3.01 eV and 2.59 eV direct energy gap in (Γ→Γ)direction by applying mBJ potential. In contrast to w– and z–ZnO the electronic structureof r–ZnO shows an indirect 2.81 eV energy gap in (Γ→L) direction. Reflectivity,transmittance and refractive index spectra for three nano layered of ZnO phases in Uv –visible region have been calculated. The electron effective mass values at the bottom ofconduction band were evaluated for the three geometries.Thu, 30 Nov 2017 20:30:00 +0100Analytical Investigation of TM Surface Waves in 1D Photonic Crystals Capped by a Self-Focusing ...
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In this paper, the localized TM surface waves of a nonlinear self-focusingleft-handed slab sandwiched between a uniform medium and a one-dimensionalphotonic crystal (1D PC) is analytically investigated. Our method is based on the firstintegral of the nonlinear Maxwell's equations. For the TM surface waves, the presenceof two electric field components makes the analysis difficult. Therefore, we used theuniaxial approximation for the nonlinear slab. The considered 1D PC can be a lefthandedPC (made of alternate left-handed (LH) and right-handed material) or a usualPC. In these structures, we find that the nonlinear LHM slab allows to control thedispersion properties of p-polarized surface waves. It is shown that there are no surfacemodes in the linear regime in the conventional PC and by increasing the intensity ofelectromagnetic field to higher value, the surface modes are emerged. To confirm ourachievements, we also comparedThu, 30 Nov 2017 20:30:00 +0100Effects of Cobalt Doping on Optical Properties of ZnO Thin Films Deposited by Sol–Gel Spin ...
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Cobalt (Co) doped Zinc Oxide (ZnO) thin films, containing different amountof Cobalt nanoparticles as the Co doping source, deposited by the sol–gel spin coatingmethod onto glass via annealing temperature at 400˚C, have been investigated by opticalcharacterization method. The effect of Co incorporation on the surface morphology wasclearly observed from scanning electron microscopy (SEM) images. Opticalconductivity and optical constants such as absorption coefficient, reflectivity, extinctioncoefficient, and refractive index as a function of photon energy were calculated, and itwas found that the doping with Co led to decrease absorption coefficient, extinctioncoefficient, refractive index and bandgap energy, while the optical conductivityincreased at higher photon energies. The optical band gap depends on the Co dopinglevel and on the particle size and crystallinity of the films and is in the range of 3.05–3.17 eV. The optical band gap widening is proportional to the one-third power of thecarrier concentration.Thu, 30 Nov 2017 20:30:00 +0100Design of an Improved Optical Filter Based on Dual-Curved PCRR for WDM Systems
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In this paper, an optical filter based on a two dimensional photonic crystalring resonator (PCRR) with triangular lattice is designed and presented. For thispurpose, the effects of positioning, arrangement and the number of the inner rods of thedual-curved PCRR on the performance characteristics of our optical filter such as thetransmission coefficient and the quality factor have been fully investigated. Calculationresults show that a transmission coefficient of 100% with a quality factor of 2400 at theoperating wavelength of nearly 1576 nm can be achieved. The proposed optical filtercomparatively performs better than the previously reported ones. In addition, thisstructure can be used for the design of optical multi-channel demultiplexer. To study thephotonic band gap of our structure, the plane wave expansion (PWE) method has beenused and the finite-difference time-domain (FDTD) method has also been employed toanalyze the optical behavior of the proposed device.Thu, 30 Nov 2017 20:30:00 +0100Temperature Tunability of Dielectric/ Liquid Crystal / Dielectric Photonic Crystal Structures
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Recently, photonic crystals doped with liquid crystal (LC) material havegained much research interest. In this article new ternary one-dimensional photoniccrystal introduced and studied. The liquid crystal layer of 5CB and 5PCH is sandwichedby two dielectric layers. For the first time, we use four structures SiO2/UCF35/CaF2,SiO2/5CB/CaF2, NFK51/UCF35/NPSK53 and NFK51/5CB/NPSK53. The effect oftemperature on transfer band gap of these photonic crystals is investigated withtransferred matrix method. The results show that in all four structures PBG forextraordinary ray (ne) is very large than ordinary ray (no) and with increasing oftemperature, PBG shifts to red wavelength. PBG width is very vast and variation of thefigure with respect temperature is very sharp for SiO2/UCF35/CaF2 structure. Also, thesuggested design takes high tunability due to the infiltration of the LC material. One canuse the proposed structureThu, 30 Nov 2017 20:30:00 +0100The Relativistic Effects on the Violation of the Bell's Inequality for Three Qubit W State
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In this paper we are going to calculate the correlation function and Bell'sinequality for three qubit W state under the Lorentz transformations. This survey is basedon the introduction of two different expressions of spin observable were presented byLee-Young and Kim-Son.Thu, 30 Nov 2017 20:30:00 +0100Tunable Defect Mode in One-Dimensional Ternary Nanophotonic Crystal with Mirror Symmetry
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In this paper, the properties of the defect mode in the photonic band gap ofone-dimensional ternary photonic crystals containing high temperature superconductorlayer (SPCs) have been theoretically investigated. We considered the quasi-periodiclayered structures by choosing two order of ternary Thue-Morse structures with mirrorsymmetry. We investigated the transmission spectra of these structures by using thetransfer matrix method and two-fluid model. It is found that the location of defect modeand the range of photonic band gap can be changed by the incident angle. So that, thedefect mode blue-shifted and disappeared by increasing the incidence angle. Weobserved an omnidirectional photonic band gap for the TE polarization that its range isfrom 456nm to 520nm. Also, the defect mode can be tuned by the temperature. As aresult, the width of defect mode can be decreased by increasing the temperature,especially in the vicinity of the critical temperature of superconductor layer. This kindof SPCs has potential applications in filters, sensors and so on.Thu, 30 Nov 2017 20:30:00 +0100