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VIIIth International Topical Meeting on Optics of Liquid Crystals (OLC 99)

作者： Kriezis, EE Elston, SJ Univ Oxford Dept Engn Sci Oxford OX1 3PJ England

Light wave propagation within complex liquid crystal structures is undertaken by the FDTD method, a purely numerical method that explicitly solves Maxwell's equations in space and time. A specific FDTD arrangement suitable for liquid crystal applications is described, allowing for efficient space termination, oblique angles of illumination, and correct phasor representation. Two application examples are considered: a two-domain twisted pixel formed by two oppositely twisted sub-domains, and a helical ferroelectric liquid crystal material. In each case comparison is also made with the optical prediction obtained by the Berreman method.

关键词： finite-difference time-domain method LC optics

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finite-difference time-domain analysis of band structures in one-dimensional Kerr-nonlinear photonic crystals

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OPTICS COMMUNICATIONS 2004年第1-3期239卷 213-222页

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

We present a new approach for analyzing band structures in one-dimensional Kerr-nonlinear photonic crystals. It combines the finite-difference time-domain method, based on the numerical simulation of oscillating dipole radiation, with the Kerr-nonlinear model. The approach is applied to analyze the band structures in Kerr-nonlinear one-dimensional photonic crystals as a function of the intensity of the oscillating dipole. We find that these bands are dynamically red-shifted with regard to the bands in linear one-dimensional photonic crystals. The proposed approach will help to understand such phenomena as intensity-driven optical limiting and all-optical switching with Kerr-nonlinear photonic crystals. (C) 2004 Elsevier B.V. All rights reserved.

关键词： one-dimensional nonlinear photonic crystal finite-difference time-domain method oscillating dipole band structure dynamic red-shift

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Analysis of guided modes in photonic crystal fibers using the finite-difference time-domain method

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MICROWAVE AND OPTICAL TECHNOLOGY LETTERS 2001年第5期30卷 327-330页

作者： Qiu, M Royal Inst Technol Dept Electromagnet Theory S-10044 Stockholm Sweden

An efficient finite-difference time-domain method is proposed for the full-wave analysis of guided modes in photonic crystal fibers. The three-dimensional hybrid guided modes can be calculated by a two-dimensional mesh, if one assumes that the propagation constant along the z-direction (propagation direction) is fixed. Furthermore, only real variables are used in the present method. Therefore, the computation time and computer memory are significantly reduced. The results for a honeycomb-based silica-air photonic crystal fiber are in very good agreement with the results from the plane-wave expansion method. (C) 2001 John Wiley & Sons, Inc.

关键词： photonic crystal fibers finite-difference time-domain method photonic crystals

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finite-difference time-domain simulation of low-F# Fresnel zone plates coupled to IR antennas

Finite-difference time-domain simulation of low-F# Fresnel z...

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Conference on Electro-Optical and Infrared Systems

作者： Rico-García, JM López-Alonso, JM Lail, B Boreman, G Alda, J Univ Complutense Madrid Sch Opt Madrid 28037 Spain

ISBN: (纸本)0819455652

Fresnel Zone Plate Lenses (FZPLs) have been successfully coupled to infrared (IR) antennas producing a responsivity enhancement of about two orders of magnitude. However, their lateral extension may compromise their applicability in focal-plane-arrays (FPA) IR imagers, where the dimensions of the pixel are constrained by the FPA spacing. When designing optimum-gain FZPLs for FPAs, we are lead to the requirement of FZPLs operating at very low F/#s (marginal rays propagating at a large angle in image space). In this case, finite-difference time-domain techniques (FDTD) are used to refine the physical-optics modelling results, producing a result closer to the actual case encountered in a high-fill-factor FPA. In this contribution, we analyze the FZPL designs by using FDTD techniques. The main result of the FDTD computation is the gain factor defined as the ratio of the response of the IR antennas coupled with the FZPL, compared to the same antennas without the FZPL.

关键词： Antennas finite-difference time-domain method Silicon Computer generated holography Infrared imaging Staring arrays Semiconducting wafers Zone plates Computer simulations Infrared radiation

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Numerical modelling of multi-dimensional liquid crystal optics: finite-difference time-domain method

MOLECULAR CRYSTALS AND LIQUID CRYSTALS

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MOLECULAR CRYSTALS AND LIQUID CRYSTALS 2001年 359卷 609-619页

作者： Kriezis, EE Elston, SJ Univ Oxford Dept Engn Sci Oxford OX1 3PJ England

关键词： finite-difference time-domain method LC optics

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finite-difference time-domain analysis of ultrashort laser pulse propagation in a fiber with nonlinear effects

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ELECTRONICS AND COMMUNICATIONS IN JAPAN PART I-COMMUNICATIONS 2004年第5期87卷 1-10页

作者： Nakamura, S Koyamada, Y Karasawa, N Sone, H Morita, R Yamashita, M Ibaraki Univ Dept Media & Telecommun Engn Hitachi Ibaraki 3168511 Japan Japan Sci & Technol Corp Core Res Evolut Sci & Technol Promot Kawaguchi 3320012 Japan Chitose Inst Sci & Technol Fac Photon Sci Chitose 0668655 Japan Kitami Inst Technol Fac Engn Kitami Hokkaido 0908507 Japan Hokkaido Univ Dept Appl Phys Sapporo Hokkaido 0618628 Japan

As a method of analyzing the nonlinear propagation of light, the Sellmeier equation for fused silica with three resonant frequencies is used and a finite-difference time-domain method taking the Raman response into account is proposed. The numerical results are compared with experimental results for optical pulses with a pulse width of 12 fs passing through a fused silica fiber. By this method of analysis, the numerical results are compared with those obtained by the conventional split-step Fourier method and it is found that these results are closer to the experimental results. (C) 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1 ,87(5): 1-10, 2004;Published online in Wiley InterScience (***). DOI 10.1002/ ecja.10166.

关键词： finite-difference time-domain method optical fiber nonlinear optics femtosecond Raman Sellmeier equation

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Higher-order finite-difference schemes with reduced dispersion errors for accurate time-domain electromagnetic simulations

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INTERNATIONAL JOURNAL OF NUMERICAL MODELLING-ELECTRONIC NETWORKS DEVICES AND FIELDS 2004年第5期17卷 461-486页

作者： Zygiridis, TT Tsiboukis, TD Aristotle Univ Thessaloniki Dept Elect & Comp Engn Appl & Computat Electromagnet Lab GR-54124 Thessaloniki Greece

The potential for developing higher-order finite-difference time-domain (FDTD) schemes with reduced phase errors is investigated in the present paper. Using the classic (2,4) FDTD method as the basis of this study, electromagnetic wave propagation is accurately reproduced in the discretized space by replacing isotropic materials with modified, anisotropic in general, ones. The use of such artificial materials improves the simulation's precision significantly around a specific frequency, yet the overall error remains small at a considerably wide bandwidth;therefore, this algorithm can be useful for wideband problems as well. Additionally, it is shown that an even better single-frequency performance can be attained, when the modified materials are combined with systematically calculated spatial operators. Pursuing a more wideband enhancement of the (2,4) technique, a version realizing more accurate results at almost all frequencies that can be coupled in a staggered grid is derived. Furthermore, novel spatial operators are introduced, with the distinct feature of using extended stencils in more than one directions. It turns out that when such operators are incorporated, a scheme that combines the aforementioned features can be obtained. The theoretical findings of this investigation are verified in a sequence of numerical tests, involving free-space and guided-wave propagation, as well as the determination of a cavity's resonant frequencies. Copyright (C) 2004 John Wiley Sons, Ltd.

关键词： finite-difference time-domain method higher-order schemes numerical dispersion optimized schemes

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Algorithm analysis on MMW dosimetry for the cell monolayer cultured in Petri dish with the FDTD method

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INTERNATIONAL JOURNAL OF INFRARED AND MILLIMETER WAVES 2004年第5期25卷 759-774页

作者： Zhao, JX Zhang, HK Liui, DG Lu, DQ Xidian Univ Sch Elect Engn Dept Biomed Engn Xian 710071 Peoples R China

Four algorithms are developed to help the dosimetry study for experiments on millimeter-wave (MMW) biological effects on cells in vitro with the finite-difference time-domain (FDTD) method. Their performances in evaluating the MMW irradiation dose are displayed and compared, including the induced current density and the specific absorption rate (SAR), that are distributed over the cell monolayer cultured in Petri dish. With the discussion on individual characteristics of the algorithms, the conclusion is reached that an appropriate algorithm is essential in providing accurate data on the MMW irradiation dose by way of numerical calculation, which should be considered carefully in related experiments.

关键词： millimeter wave dosimetry cell monolayer Petri dish finite-difference time-domain method

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Effects of weighting and damping coefficients on the accuracy of Higdon-based absorbing boundary conditions

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MICROWAVE AND OPTICAL TECHNOLOGY LETTERS 2004年第6期41卷 446-448页

作者： Wu, X Ramahi, OM Univ Maryland Dept Mech Engn A James Clark Sch Engn College Pk MD 20742 USA Univ Maryland Dept Elect & Comp Engn A James Clark Sch Engn College Pk MD 20742 USA Univ Maryland CALCE Elect Prod & Syst Ctr A James Clark Sch Engn College Pk MD 20742 USA

In this work, the effects of weighted difference schemes and damping factor on the spurious errors arising from the application of Higdon's absorbing boundary condition and the concurrent complementary operators method (C-COM) are investigated. An optimized combination of the weighted difference scheme for boundary conditions and the damping term used to stabilize the boundary scheme are proposed to minimize the reflections. (C) 2004 Wiley Periodicals, Inc.

关键词： absorbing boundary condition (ABC) finite-difference time-domain method concurrent complementary operators method stability

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Optimal design of PML absorbing boundary condition for improving wide-angle reflection performance

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ELECTRONICS LETTERS 2004年第2期40卷 104-106页

作者： Kim, S Choi, JH Hanyang Univ Dept Elect & Comp Engn Seoul 133791 South Korea

A method to optimise the angle reflection performance of Berenger's perfectly matched layer (PML) absorbing boundary condition for finite-difference time-domain (FDTD) method is described. By specifying the conductivity in each of the PML sublayers, the wide-angle reflection performance can be improved. To improve the angle reflection performance as well as to reduce the discretisation error characteristic due to the FDTD approximation, a two-step conductivity profile is used in PML. To obtain the optimal value for each conductivity profile, the micro-genetic algorithm method is employed. Using this method, good wide-angle reflection performance of PML is achieved.

关键词： two-step conductivity profile electromagnetic wave reflection boundary-value problems finite-difference time-domain method Electromagnetic waves: theory conductivity finite difference time-domain analysis Other numerical methods Electromagnetic wave propagation genetic algorithms electrical conductivity wide-angle reflection performance perfectly matched layer absorbing boundary condition micro-genetic algorithm method PML absorbing boundary condition optimal design electromagnetic wave absorption improving wide-angle reflection performance

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