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Design of two-dimensional photonic crystal structure based in all-angle negative refractive effect for application in focusing systems

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IET OPTOELECTRONICS 2007年第2期1卷 91-95页

作者： Belhadj, W. Gamra, D. AbdelMalek, F. Haxha, S. Bouchriha, H. Natl Inst Appl Sci & Technol Tunis 1080 Tunisia Fac Sci Tunis Dept Phys Quantum Phys & Photon Grp Tunis 1060 Tunisia Univ Kent Dept Elect Broadband & Wireless Commun Grp Canterbury CT2 7NT Kent England

A design of a polarisation independent focusing system of electromagnetic waves in a two-dimensional photonic crystal (PC) is proposed and numerically demonstrated by using the finite-difference time-domain method. We have shown that by the careful selection of both the refractive index of the high index material and the air cylinder radius, a complete all-angle negative refraction can be obtained for both the transverse electric (TE) and the transverse magnetic (TM) polarisations. We have demonstrated that the proposed PC structures can focus either the TE or the TM or both TE and TM polarised waves with sub-wavelength resolution. In addition, a significant improvement of the image resolution has been presented.

关键词： all-angle negative refractive effect light refraction negative refraction finite difference time-domain analysis light polarisation Photonic band gap (condensed matter) image resolution refractive index photonic crystals transverse electric polarisation finite-difference time-domain method Photonic bandgap materials high index material two-dimensional photonic crystal transverse magnetic polarisation focusing systems optical focusing Optical constants and parameters (condensed matter)

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Nano-optical investigation of enhanced field at gold nanosphere-gold plane junctions

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BULLETIN OF THE KOREAN CHEMICAL SOCIETY 2007年第12期28卷 2200-2202页

作者： Ahn, Sung-Hyun Park, Won-Hwa Kim, Zee Hwan Korea Univ Dept Chem Seoul 136701 South Korea Korea Univ Ctr Photo & Elect Responsive Mol Seoul 136701 South Korea

The local field distribution around gold nanosphere-gold plane junction has been studied using the finite-difference time-domain (FDTD) electrodynamics calculation procedure. We find that both the in-plane and out-of-plane polarized excitation produce enhanced field strong enough to explain the observed SERS activities of the junctions. Comparison with a simple dipole-image dipole model shows that the enhanced field primarily originates from the multipole-image multipole interaction, which indicates that the detailed fine-structures of the nanoparticles also play a significant role in the SERS activities as well.

关键词： surface plasmons surface-enhanced Raman scattering finite-difference time-domain method metal nanoparticles dipole-coupling

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Treatment of arbitrarily-orientated multiwire bundles and terminated multiwire transmission lines in FDTD method

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IET MICROWAVES ANTENNAS & PROPAGATION 2007年第2期1卷 381-387页

作者： Zhang, G. Railton, C. J. Univ Bristol Ctr Commun Res Bristol BS8 1UB Avon England

The finite-difference time-domain (FDTD) method is extremely versatile and widely used but there still remain structures in which the method encounters serious difficulties. One such situation is the analysis of bundles of closely spaced wires which are not parallel to the FDTD mesh. Similar problems are encountered in the analysis of multiconductor transmission lines such as PCB tracks. Recent research has yielded methods for treating single wires, orientated at an angle to the FDTD mesh, and for treating multiwire bundles which are aligned with the mesh, but not for both situations at once. In the paper, an enhanced method is presented which allows the treatment of wire bundles, including those which are arbitrarily orientated with respect to the mesh and those which may also be terminated with lumped components. Results are provided that show the consistency and accuracy of the proposed technique.

关键词： multiconductor transmission lines finite difference time-domain analysis transmission line theory finite-difference time-domain method terminated multiwire transmission lines Other numerical methods Transmission line theory FDTD method

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Phenomenological studies of optical properties of Cu nanowires

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SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2007年第4期8卷 277-281页

作者： Locharoenrat, Kitsakorn Sano, Haruyuki Mizutani, Goro Japan Adv Inst Sci & Technol Sch Mat Sci Nomi Ishikawa 9231292 Japan JAIST 21st COE Program Nomi Ishikawa 9231292 Japan

We report on the experimental observation of surface plasmon resonance in Cu nanowires fabricated by shadow deposition method. When the incident light is polarized perpendicular to the wire axes, plasmon maxima appeared Lit about 2.3 eV in the absorption spectra. Plasmon resonance appeared at lower photon energy when the incident light is polarized parallel to the wire axes. Resonance peaks move to lower energy when the nanowire widths are increased. We have found that finite-difference time-domain (FDTD) simulation gives better results than Maxwell-Garnett model in explaining the relation between the light polarization and the energies of the observed absorption maxima. (C) 2007 NIMS and Elsevier Ltd. All rights reserved.

关键词： metals nanowires optical spectroscopy Maxwell-Garnett model surface plasmon resonance finite-difference time-domain method

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Exponential time differencing FDTD formulation for plasma

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MICROWAVE AND OPTICAL TECHNOLOGY LETTERS 2007年第6期49卷 1363-1364页

作者： Huang, Sh. J. Zhanjiang Normal Univ Dept Phys Zhanjiang 524048 Guangdong Prov Peoples R China

The exponential tune differencing (ETD) schemes are proposed for transient propagation in dynamic collision plasmas using finite-difference time-domain method. The formulation of ETD algorithms with the first order and second accuracy is presented. The ETD algorithms are validated by comparing the simulation results with analytical values. The numerical results indicate that the ETD schemes are accurate and efficient. (c) 2007 Wiley Periodicals, Inc.

关键词： finite-difference time-domain method exponential time differencing dispersive media plasma

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Radiative properties of gold surfaces with one-dimensional microscale gaussian random roughness

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INTERNATIONAL JOURNAL OF THERMOPHYSICS 2007年第2期28卷 598-615页

作者： Fu, Kang Hsu, Pei-feng Florida Inst Technol Dept Mech & Aerosp Engn Melbourne FL 32901 USA

The radiative properties of engineering surfaces with microscale surface textures depend on the incident wavelength, optical properties, and temperature as well as the topography of the reflective surface. In the case of slightly rough surfaces, the traditional Kirchhoff theory on rough surface scattering may be applicable. In this study, a direct numerical solution of Maxwell's equations was developed to understand scattering from weakly to very rough surfaces. The method is the finite-difference time-domain method. The problem of interest is a set of gold surfaces with Gaussian random roughness distributions. Highly accurate experimental data are available from the earlier work of Knotts and O'Donnell in 1994. Due to the negative real component of the complex dielectric constant at the infrared light source wavelengths of 1.152 and 3.392 mu m, the convoluted integral was used to convert the frequency domain electrical properties to time-domain properties in order to obtain convergent solutions. The bi-directional reflectances for both normal and parallel polarizations were obtained and compared with experimental data. The predicted values and experimental results are in good agreement. The highly specular peak in the reflectivity was reproduced in the numerical simulations, and the increase of the parallel polarization bi-directional reflectance was found to be due to the effect of a variation in the optical constant from 1.152 to 3.392 mu m.

关键词： bi-directional reflectance finite-difference time-domain method gold surface random roughness

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90° bent metallic waveguide with a tapered C-shaped aperture for use in HAMR

90° bent metallic waveguide with a tapered C-shaped apertur...

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Topical Meeting on Optical Data Storage

作者： Leen, J. Brian Cho, Eunhyoung Suh, Sung-Dong Hansen, Paul C. Sohn, Jin-Seung Choa, Sung-Hoon Hesselink, Lambertus Stanford Univ Dept Appl Phys Stanford CA 94305 USA Samsung Adv Inst Technol Suwon South Korea

ISBN: (纸本)9780819467621

An efficient and compact method of introducing light into a magnetic recording head for use in Heat Assisted Magnetic Recording (HAMR) is proposed. The technique uses a polymer waveguide to source light into a novel metallic structure consisting of a sub-wavelength G aperture waveguide with a 90 degrees bend and a tapered section. The structure is modeled using finite difference time domain (FDTD) simulations and it is shown that the 90 degrees bend allows for low loss near-field optical access into a conventional magnetic recording head while the tapered G waveguide allows for maximum input coupling and a minimum spot size at the recording media.

关键词： Waveguides Magnetism Head Near field optics Polymer multimode waveguides Polymers Light finite-difference time-domain method Gold Near field

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Influence of thickness of perfectly conducting plate on its scattering characteristics

Influence of thickness of perfectly conducting plate on its ...

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6th International Conference on Antenna Theory and Techniques

作者： Soldatenkov, V. P. Byelarussian State Univ Informat & Radioelect Minsk 220013 BELARUS

Scattering characteristics of perfectly conducting rectangular flat plate are analyzed for frequency region near resonance. The finite-difference time-domain method is used in simple and efficient form. Scattering dia... 详细信息

ISBN: (纸本)9781424415847

关键词： finite-difference time-domain method integral equation method scattering diagram conducting plate

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Two-dimensional photonic crystal polarizer modulated by silicon resin

Two-dimensional photonic crystal polarizer modulated by sili...

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Conference on Optoelectronic Materials and Devices II

作者： Tan, Chunhua Huang, Xuguang S China Normal Univ Sch Informat & Optoelect Sci & Engn Lab Photon Informat Technol Guangzhou 510631 Peoples R China

ISBN: (纸本)9780819469458

Photonic crystals(PCs)have many potential applications because of their ability to control light-wave propagation. In this paper, we theoretically investigate the tunability of light propagation in photonic crystal waveguides in two-dimensional photonic crystals with square lattices composed of heat-resistant silicon resin. Waveguides can be obtained by the infiltration of silicon resin into air regions in two-dimensional photonic crystals composed of air holes with square lattices of dielectric cylinders. The refractive index of silicon resin can be changed by manipulating the temperature of the sample. Numerical simulation by solving Maxwell's equations using the plane wave expansion(PWE) method shows that the band gaps can be continuously tuned by silicon resin, accordingly the light propagation in photonic crystal waveguides can be controlled. The band gap is analyzed in the temperature range of 20 degrees C-120 degrees C. In our work, the gap map for a square lattice of dielectric cylinders is also simulated. The method can separate TM- and TE-polarized modes in the waveguide. Such a mechanism of band gap adjustment should open up a new application for designing field-sensitive polarizer in photonic integrated circuits.

关键词： photonic crystal photonic band gap plane wave expand method finite-difference time-domain method polarizer heat-resisitant silicon resin Maxwell's equation

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Strong mode coupling, bistable lasing, and switching mode dynamics in twin coupled microcavities

Strong mode coupling, bistable lasing, and switching mode dy...

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ICONO 2007 Conference

作者： Zhukovsky, S. V. Chigrin, D. N. Lavrinenko, A. V. Kroha, J. Univ Bonn Inst Phys Nussallee 12 D-53115 Bonn Germany

ISBN: (纸本)9780819468826

Bistable lasing in twin coupled microcavities is demonstrated analytically and numerically, underlying a new principle of a multiple-wavelength microlaser where the lasing wavelength is switched by locking into the desired mode in a multimode resonator. The bistability appears due to an interplay between coherent and incoherent mode interaction processes, assisted by similarity between the spatial intensity distribution of the modes in the gain region. The wavelength switching dynamics in a model system of twin defects in a photonic crystal is explained on the basis of the theoretical analysis presented.

关键词： Switching Resonators Bistability Optical microcavities Laser resonators Polarization finite-difference time-domain method Hole burning spectroscopy Bistable lasers Photonic crystals

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