检索结果-内蒙古大学图书馆

Reducing the dispersion errors of the finite-difference time-domain method for multifrequency plane-wave excitations

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ELECTROMAGNETICS 2003年第6期23卷 539-552页

作者： Oguz, U Gürel, L Bilkent Univ Dept Elect & Elect Engn TR-06800 Ankara Turkey

We demonstrate the applications of discrete-time signal-processing (SP) techniques for the purpose of generating accurate plane waves in the finite-difference time-domain (FDTD) method. The SP techniques are used either to reduce the high-frequency content of the source excitation or to compute more precise incident-field values in the computational domain. The effects of smoothing windows of various lengths, digital lowpass filters of various bandwidths and characteristics, and polynomial interpolation schemes of various orders are investigated. Arbitrary signals with multifrequency content are considered.

关键词： finite-difference time-domain method plane-wave excitation numerical dispersion sampling windowing digital filters

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Design of polarization band-pass filter of one-dimensional photonic crystal nanometer film in the range of visible light

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Guangdian Gongcheng/Opto-Electronic Engineering 2007年第5期34卷 33-37页

作者： Tang, Bing-Shu Department of Physics Lianyun-gang Teacher's College Lianyungang 222006 China Department of Physics Jiangsu University Zhenjiang 212003 China

One-dimensional finite-difference time-domain method (1-D FDTD) is used in the study and design of polarization filter of one-dimensional photonic crystal nanometer film in the range of visible light. The numerical results indicate that traditional optical multi-layer films are the special case of one-dimensional binary photonic crystals. The filter properties of one-dimensional binary photonic crystals are dependent on a variety of factors, such as the position and thickness of doping layer, the electromagnetic parameters and incident angles. When the doping layer is in the middle of the film, the effect of polarization separation is the best. The larger the difference of thickness between doping layer and periodic layer is, the better the effect of polarization separation is. The forbidden band can be formed if the difference between the refraction indices of two-component is big enough. The incident angle of light and the materials loss both take effect on the filter properties of above structure. All the results play an important role in future design of photonic device.

关键词： finite-difference time-domain method Forbidden band One-dimensional binary photonic crystal Polarization filter properties

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Numerical investigation of the parameter dependences of nanolithography by using micro-structured metal grating

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JOURNAL OF OPTICS A-PURE AND APPLIED OPTICS 2007年第5期9卷 506-510页

作者： Zhao, Peng Wang, Yan-hua Zhang, Yan Capital Normal Univ Dept Phys Beijing 100037 Peoples R China

The electric field distribution of the micro-structured metal grating is investigated by using the finite-difference time-domain method. The simulation results show that the electric field distribution is strongly dependent on the structure's periodicity, the grooves' depth and the distance between groove and slit. Adjusting the parameters of the grating can modify the transmitted field distribution, which provides a valid way for high resolution photolithography.

关键词： nanolithography surface plasmons finite-difference time-domain method

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FDTD study on back scattering of conducting sphere coated with double-negatibe metamaterials

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INTERNATIONAL JOURNAL OF INFRARED AND MILLIMETER WAVES 2007年第2期28卷 199-206页

作者： Wang, Maoyan Ge, Debiao Xu, Jun Wu, Jian Univ Elect Sci & Technol China Inst Appl Phys Chengdu 610054 Peoples R China Xidian Univ Dept Phys Xian 710071 Peoples R China Natl Key Lab Electromagnet Environm Beijing 102206 Peoples R China

The shift operator method in finite-difference time-domain method for anisotropic double-negative (DNG) metamaterials is derived. The problem which incorporates both anisotropy and frequency dispersion at the same time is solved for the electromagnetic wave propagation in DNG media. By comparing with the mie series solution, the numerical verification of the method and program are confirmed by computing the back scattering of isotropic unmagnetized plasma sphere. The back scattering of conducting sphere coated with DNG media with different parameters is computed by using the shift operator method. One finds that the degree of DNG media's match and isotropy plays important parts in the decrease of the back scattering of the conducting sphere.

关键词： double-negative metamaterials finite-difference time-domain method back scattering anisotropic plasma

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Threshold behavior of defect modes in one-dimensional active photonic crystal

Threshold behavior of defect modes in one-dimensional active...

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2007年中国青年光学学术研讨会

作者： Wang Hong~(a,b) Ouyang Zheng biao~(*a) Han Yanling~(c,d) ~aCenter of THz Technology of Shenzhen University,College of Engineering and Technology,Shenzhen University, Shenzhen 518060,China ~bUniversity of Electronic Science and Technology of China,School of Physical Electronics,Chengdu 100718,China ~cState Education Commission Laboratory for Image Processing & Intelligent Control,Institute of Artificial Intelligence,Huazhong University of Science & Technology,Wuhan 430074,China ~dphysics Department of China University of Geosciences,Wuhan 430074,China

Based on a model of coupling Maxwell's equations with the rate equations of electronic population,the spatial-distribution and spectrum-characteristics as well as amplified properties of defect modes such as lasing threshold,saturated output in a single-defect active photonic crystal are investigated through finite-difference time-domain *** of the number of crystal periods and spatial profile on amplified feature are also *** results show that the lasing threshold and saturated output depend directly on the number of crystal periods and the spatial profile of defect modes;the defect mode with lower mode area has a ***,the lasing threshold can be further reduced as the saturated output increases if the number of crystal periods *** a feature is important for understanding of the interaction between optical gain and defect modes.

关键词： laser physics photonic crystal laser finite-difference time-domain method defect mode

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Optical modulator using silicon photonic crystals/nano-montmorillonite

Optical modulator using silicon photonic crystals/nano-montm...

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2007亚洲光电子会议纳米光子学/纳米结构/纳米计量学分会场

作者： Jiu-sheng Li,Jian-rui Li,Xiu-ming Wang Centre for THz Research,China Jiliang University,Hangzhou 310018,China School of Information Engineering,China Jiliang University,Hangzhou 310018,China

In this paper,a novel compact optical modulator based on silicon photonic crystals /nano-montmorillonite is *** two-dimensional silicon photonic crystal with triangular lattice and a line defect waveguide formed by a missing row of air holes in theΓ-K *** lattice constant is a,and the diameter of the holes is d=*** holes are filled with the nano-montmorillonite electrorheological fluid,which is made of nanometer sized *** light modulation mechanism of the novel modulator is based on a dynamic shift of the photonic band *** have investigated its light modulation performance by using the finite-difference time-domain *** numerical results show that an excellent optical modulator at a wavelength of 1550nm is *** novel modulator has a high extinction ratio(close to-40dB)and small size(around 10μm).It is very suitable for forthcoming photonic integrated circuits.

关键词： Nano-montmorillonite finite-difference time-domain method Modulator Photonic crystals

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Beam adaptive single arm rectangular spiral antenna with switches

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IEE PROCEEDINGS-MICROWAVES ANTENNAS AND PROPAGATION 2006年第1期153卷 13-18页

作者： Mehta, A Mirshekar-Syahkal, D Nakano, H Univ Essex Dept Elect Syst Engn Colchester CO4 3SQ Essex England Hosei Univ Dept Elect Informat Koganei Tokyo 1848584 Japan

A rectangular spiral antenna with switches is proposed for beam adaptive applications. The excitation of switches introduces variations in the current distribution oil the antenna arm, thus causing the beam to steer. A switch is implemented as an element to short-circuit at a point on the spiral ann to the ground conductor (shorted spiral antenna). A shorted spiral configuration using four switches is analysed. For this configuration, both single- and multipoint switching are implemented. Sixteen possible switching cases are investigated. The radiation patterns are measured in the Satimo antenna test facility and numerically supported using the finite-difference time-domain (FDTD) method. Tilted (24 degrees < 0(max) < 44 degrees) and axial (5 degrees < 0(max) < 12 degrees) beams are obtained using various switching cases, thus realising an adaptive antenna. The gain, which is approximately 6.5 dBi, stays uniform within +/- 1 dB variation and the VSWR remains within an acceptable limit or 2 for the majority of the switching cases.

关键词： finite difference time-domain analysis antenna arm Antenna arrays beam steering test facilities single-point switching rectangular waveguides adaptive application radiation pattern finite-difference time-domain method antenna radiation patterns rectangular spiral antenna adaptive antenna arrays current distribution multipoint switching spiral antennas Satimo antenna test facility Waveguides and microwave transmission lines antenna testing Other numerical methods ground conductor FDTD

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An FDTD analysis of nonlinear photonic crystal waveguides

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OPTICAL AND QUANTUM ELECTRONICS 2006年第1-3期38卷 149-160页

作者： Maksymov, IS Marsal, LF Pallarès, J Univ Rovira & Virgili Dept Engn Elect Elect & Automat Tarragona 43007 Spain

We present a modelling technique for analyzing dispersion characteristics of nonlinear photonic crystal waveguides. This technique combines the nonlinear finite-difference time-domain method, based on the numerical simulation of oscillating dipole radiation, with the super cell approach and the periodic boundary conditions. The technique presented makes it possible to calculate the dispersion characteristics of Kerr-like nonlinear photonic crystals waveguides made by removing some scatterers. A numerical tool based on this technique can be used to design various components for integrated optical circuits.

关键词： finite-difference time-domain method Kerr-like nonlinear material photonic crystal red-shift waveguide

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Numerical modeling of optically controlled dielectric reasonators

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INTERNATIONAL JOURNAL OF INFRARED AND MILLIMETER WAVES 2006年第1期27卷 55-64页

作者： Zheng, Hong-Xing Ding, Ju-Chao Yu, Dao-Yin Tianjin Univ Coll Precis Instrument & Optoelect Engn Tianjin 300072 Peoples R China

To analyze the optically controlled dielectric resonators accurately, an efficient numerical modelling technique is proposed in this paper. By using alternating-direction implicit finite-difference time-domain method and conformal technique, the resonant frequency of a dielectric resonator is calculated. In addition, an optical generation of plasma is used as a possible means of controlling the resonate frequency, and the effect that solid state plasmas have on the resonator's frequency is described. The numerical results agree very well with measurements in estimation of the optically induced resonator's frequency-shift.

关键词： alternating-direction implicit conformal algorithm dielectric resonators finite-difference time-domain method frequency dependent

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Effects of shaded facets on the performance of metal-coated etched diffraction grating demultiplexer

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OPTICS COMMUNICATIONS 2006年第1期266卷 117-121页

作者： Zhu, Ning Song, Jun Shao, Liyang Zhejiang Univ Ctr Opt & Electromagnet Res State Key Lab Modern Opt Instrumentat Joint Lab Opt Commun Hangzhou 310027 Peoples R China

A finite-difference time-domain (FDTD) method combined with a periodic boundary condition is used to analyze the diffraction efficiency of an etched diffraction grating (EDG) demultiplexer coated with a metallic film at the backside. The numerical results show that the diffraction loss is mainly due to the scattering effect of shaded facets of a metal-coated grating at both the polarizations. However, the same shaded facets can produce a higher loss for a TM polarization than that for a TE polarization, which induces a higher polarization dependent loss (PDL) of the demultiplexer. (c) 2006 Elsevier B.V. All rights reserved.

关键词： finite-difference time-domain method etched diffraction grating perfectly matched layer diffraction efficiency

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