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Conference on Physics, Simulation, and Photonic Engineering of Photovoltaic Devices VIII

作者： Hussein, Mohamed Mahmoud, Korany R. Hameed, Mohamed Farhat O. Obayya, S. A. Zewail City Sci & Technol Ctr Photon & Smart Mat 6Th Of October City Egypt Ain Shams Univ Fac Sci Phys Dept Cairo Egypt Helwan Univ Elect Commun & Comp Dept Fac Engn Helwan Egypt Zewail City Sci & Technol Nanotechnol Engn Program 6Th Of October City Egypt Mansoura Univ Fac Engn Mansoura Egypt

ISBN: (纸本)9781510624696

Nowadays, the efficiency improvement of the silicon solar cells (SCs) is a hot research topic in photovoltaic industry. Silicon nanowires (Si-NWs) offer a promising candidate for low-cost SCs with high-efficiency due to their unique optical and electrical properties. The Si-NWs can achieve highly efficient light trapping with reduced cost. In this paper, a novel design of asymmetric tapered nanocone Si-NWs is introduced and analyzed by 3D finite difference time domain (FDTD) method. The particle swarm optimization (PSO) technique is also used to optimize the geometrical parameters of the suggested design to maximize the optical efficiency of the suggested SC. The asymmetric Si-NWs offer an ultimate efficiency of 39.6 % with an improvement of 24 % relative to the conventional symmetric nanocone Si-NWs.

关键词： Absorption Particles Particle swarm optimization finite-difference time-domain method Nanowires Solar cells Silicon Communication engineering Photovoltaics Photonics

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Quantifying Subgridding Errors when Modeling Multiscale Structures with FDTD

Quantifying Subgridding Errors when Modeling Multiscale Stru...

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International Symposium of Applied-Computational-Electromagnetics-Society (ACES)

作者： Le, Madison Hadi, Mohammed Elsherbeni, Atef Colorado Sch Mines Elect Engn Dept Golden CO 80401 USA

ISBN: (纸本)9780996007887

This paper discusses the growing subgridding errors in finite-difference time-domain (FDTD) analysis when applied on electrically large subgrids. FDTD simulations in 1D and 2D spaces are used with a 1:3 contrast ratio. Error levels are found to be linearly proportional to the subgrid's electrical dimension along the wave's propagation path. This linear growth suggests numerical phase error mismatch between coarse and fine grids as the subgridding error source.

关键词： finite-difference time-domain method numerical error analysis subgridding multi-scale problems

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time-domain development of negative refraction

Time-domain development of negative refraction

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International Symposium of Applied-Computational-Electromagnetics-Society (ACES)

作者： Garner, Timothy J. US Army Radio Frequency Commun Div CERDEC Aberdeen Proving Ground MD 21005 USA

ISBN: (纸本)9780996007887

Negative refraction in prisms built of periodic unit cells is a steady-state phenomenon that requires a finite amount time to develop. A signal transmitted through such a prism will initially be refracted positively. As time increases, the direction of refraction shifts toward the steady state angle of refraction. Signals that are shorter than the time required to reach steady state are not negatively refracted.

关键词： negative refraction finite-difference time-domain method periodic structures metamaterials

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GROUND PENETRATING RADAR DATA INTERPRETATION USING ELECTROMAGNETIC FIELD ANALYSIS FOR SEA ICE THICKNESS MEASUREMENT

GROUND PENETRATING RADAR DATA INTERPRETATION USING ELECTROMA...

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ISPRS Technical Commission III WG III/2, 10 Joint Workshop on Multidisciplinary Remote Sensing for Environmental Monitoring

作者： Matsumoto, M. Yoshimura, M. Naoki, K. Cho, K. Wakabayashi, H. PASCO CORP Meguro Ku 2-8-10 Higashiyama Tokyo Japan Univ Tokyo Ctr Spatial Informat Sci Meguro Ku Tokyo Japan Tokai Univ Shibuya Ku 2-28-4 Tomigaya Tokyo Japan Nihon Univ 1 Nakagawara Koriyama Fukushima Japan

Observation of sea ice thickness by remote sensing is one of key issues to understand an effect of global warming. However, ground truth must be necessary to discuss this kind of approach. Although there are several methods to acquire ice thickness, Ground Penetrating Radar (GPR) can be good solution because it can discriminate snow-ice and ice-sea water interface thanks to comparative higher spatial resolution than the other methods. In this paper, we carried out GPR measurement in brackish lake and an electromagnetic field analysis in order to interpret the GPR data. The simulation model was assumed considering the actual snow and ice thickness acquired in field measurement. From the simulation results, although it seems difficult to identify the reflection at snow and ice interface due to a thin layer thickness and a low dielectric constant, snow and ice thickness may be estimated by using multiple reflection components.

关键词： Sea ice thickness measurement Ground truth Ground Penetrating Radar Brackish lake finite-difference time-domain method Dielectric constant Multiple reflection

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Active plasmonic nanoantenna-based switch for controlling near-field properties 9

Active plasmonic nanoantenna-based switch for controlling ne...

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Conference on Photonic and Phononic Properties of Engineered Nanostructures IX

作者： Gupta, Nitin Savaliya, Priten B. Subramanian, Senthil Dhawan, Anuj Indian Inst Technol Delhi Dept Elect Engn Hauz Khas New Delhi 110016 India

ISBN: (纸本)9781510624979

We present a plasmonic switch - based on a combination of plasmonic nanoantennas and a phase-change material such as vanadium dioxide (VO2) - that exhibits great potential for switching the near-field around the nanoantenna at ultrafast time-scales. In order to characterize the switch, we employed the FDTD method to calculate the intensity switching ratio in the vicinity of the nanoantennas - i.e. the ratio of the electric-field intensity between the metallic state (On-state) and the semiconductor state (Off-state) of the VO2 material. The proposed switch exhibits an intensity switching ratio which is much higher as compared to those reported previously.

关键词： Nanoantennas Plasmonics Switches Near field finite-difference time-domain method Active plasmonics

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Absorbing Boundary Condition of FDTD method Based on Surface Equivalence Theorem Using Spherical Harmonics Expression 21

Absorbing Boundary Condition of FDTD method Based on Surface...

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21st International Conference on Electromagnetics in Advanced Applications (ICEAA)

作者： Kawaguchi, Hideki Muroran Inst Technol Dept Elect & Informat Engn Muroran Hokkaido Japan

ISBN: (纸本)9781728105635

This paper considers speed-up of a calculation of an absorbing boundary condition (ABC) of the finite-difference time-domain (FDTD) method based on a time-domain surface integral equation. The most popular ABC of the FDTD method, the perfectly matched layer (PML), is still required to be modified for its accuracy in cases of near field and large incident angle to ABC. The ABC based on the time-domain surface integral equation is free from such confinements of the ABC location and incident angle. On the other hand, it is known that extremely heavy computation cost is required for the time-domain surface integral. In this work, it is attempted to reduce the computation cost of the surface integral equation to use spherical harmonics expression for harmonic Green's function in the surface integral equation.

关键词： finite-difference time-domain method absorbing boundary condition perfectly matched layer time-domain surface integral equation surface equivalent theorem electric and magnetic surface charge and current densities spherical harmonics expression multi-pole expansion

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Silicon-based plasmonic nanoantennas 14

Silicon-based plasmonic nanoantennas

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Conference on Silicon Photonics XIV

作者： Mekawey, Hosam I. Ismail, Yehea Swillam, Mohamed A. Amer Univ Cairo Ctr Nanoelect & Devices Cairo Egypt Zewail City Sci & Technol Giza Egypt Amer Univ Cairo Cairo Egypt

ISBN: (数字)9781510624894

ISBN: (纸本)9781510624894

In this work, silicon-based plasmonic nanoantennas was realized. Using silicon instead of metals as the material of choice in building such nanoantennas is advantageous as it enables the integration of nanoantennas-based structures into integrated-optoelectronics circuits built using the standard fabrication techniques in the electronic industry. It also allows for low cost mass production of the proposed devices. Upon light incidence on an array of nanoantennas, Localized Surface Plasmon Resonance (LSPR) is generated which causes an enhancement in the localized field inside the structure and in the near field zone. The enhanced localized field is manifested as an enhancement in the absorbed as well as the scattered field. Varying the surrounding material causes variations in the wavelength of the enhancement peak as well as the enhancement level itself. Hence, sensors can be built to facilitate sensing molecules with its characteristic vibrational transitions. In this paper, dipole and bowtie silicon nanoantennas are investigated. It is found that when using silicon with high excess carrier concentrations as the material of choice, the enhancement occur in the mid-IR spectral range which is red shifted compared to the enhancement produced when using metal such as gold or silver. Working in mid-IR is advantageous for sensing applications as the characteristic vibrational transitions of the majority of bio-chemical molecules happens in the mid-IR.

关键词： Silicon Nanoantennas Gold Plasmonics finite-difference time-domain method Mid-IR Resonance enhancement Metals Surface plasmons

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Protective Effect of Shield Wires Against Direct Lightning Flashes to Buried Cables

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IEEE TRANSACTIONS ON POWER DELIVERY 2018年第4期33卷 1628-1635页

作者： Tanaka, Hiroki Baba, Yoshihiro Barbosa, Celio Fonseca Tsuboi, Toshihiro Okabe, Shigemitsu Doshisha Univ Dept Elect Engn Kyoto 6100321 Japan R&D Ctr Telecommun CPqD BR-13086902 Campinas SP Brazil Tokyo Elect Power Co Ltd Tokyo Elect Power Co Res Inst Yokohama Kanagawa 2308510 Japan

The protective effect of a shield wire against direct lightning flashes to a buried power cable has been clarified in this paper. The finite-difference time-domain (FDTD) method is used in the investigation. The FDTD model considers a 1-km-long insulated cable protected by a shield wire, and a lightning strike right above them. The model has been validated by comparing its results with experimental results available in the literature. The computed results show that the presence of the shield wire can effectively prevent the cable from being directly struck by the lightning flash. The voltage across the cable insulation at the striking point depends on the ground resistivity (the higher the resistivity, the higher the voltage), but this dependence is not linear. It is also shown that the soil surface ionization is relevant to the current delivered to the shield wire and to the voltage developed across the cable insulation. On the other hand, the soil ionization around the shield wire has negligible effects. The intrinsic resistance of the shield wire does not influence significantly the peak voltage across the cable insulation, but it influences its duration (the higher the intrinsic resistance, the longer the voltage duration).

关键词： Cable insulation electromagnetic shielding finite-difference time-domain method lightning protection

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Impact of Ag@SiO₂ core-shell nanoparticles on the photoelectric current of plasmonic inverted organic solar cells

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SYNTHETIC METALS 2018年 239卷 22-28页

作者： N'Konou, Kekeli Chalh, Malika Monnier, Virginie Blanchard, Nicholas P. Chevolot, Yann Lucas, Bruno Vedraine, Sylvain Torchio, Philippe Aix Marseille Univ IM2NP CNRS Serv 231UMR 7334 Domaine Univ St Jerome F-13397 Marseille 20 France Univ Limoges XLIM CNRS 7252 123 Ave Albert Thomas F-87060 Limoges France Univ Lyon Inst Nanotechnol Lyon UMR CNRS 5270 Ecole Cent Lyon 36 Ave Guy de Colongue F-69134 Ecully France Univ Claude Bernard Lyon 1 Univ Lyon CNRS Inst Lumiere Matiere F-69622 Villeurbanne France

We report on the influence of silver-silica core-shell nanoparticles (Ag@SiO(2)NPs) and bare silver nanoparticles (Ag NPs) on the photoelectric current of plasmonic inverted organic solar cells. The synthesized Ag@SiO(2)NPs are deposited on a zinc oxide layer. The optimized plasmonic devices concern the Ag@SiO(2)NPs with 5 nm shell thickness and present the highest short-circuit current density of 13.44 mA/cm(2), enhanced by 12% compared to the reference device. Such enhancements can mainly be attributed to the localized surface plasmon resonance and to the light scattering effect originating from Ag NPs and Ag@SiO(2)NPs. finite-difference time-domain simulation reveals that a thin shell thickness facilitates the extension of a strong localized enhanced electromagnetic field in the active layer, as confirmed by measured and simulated optical absorption and photoluminescence measurements. Furthermore, AFM images present a well-distributed Ag@SiO(2)NPs array on the ZnO films, which contributes to such an improvement.

关键词： Ag@SiO2 core-shell nanospheres Plasmonic solar cells Absorption enhancement finite-difference time-domain method

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Morphologies and optical and electrical properties of InGaN/GaN micro-square array light-emitting diode chips

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APPLIED OPTICS 2018年第11期57卷 2835-2840页

作者： Han, Dan Ma, Shufang Jia, Zhigang Liu, Peizhi Jia, Wei Shang, Lin Zhai, Guangmei Xu, Bingshe Taiyuan Univ Technol Minist Educ Key Lab Interface Sci & Engn Adv Mat Taiyuan 030024 Shanxi Peoples R China Taiyuan Univ Technol Res Ctr Adv Mat Sci & Technol Taiyuan 030024 Shanxi Peoples R China Shaanxi Univ Sci & Technol Inst Atom & Mol Sci Xian 710021 Shaanxi Peoples R China

InGaN/GaN micro-square array light-emitting diode (LED) chips (micro-chips) have been prepared via the focused ion beam (FIB) etching technique, which can not only reduce ohmic contact degradation but also control the aspect ratio precisely in three-dimensional (3D) structure LED (3D-LED) device fabrication. The effects of FIB beam current and micro-square array depth on morphologies and optical and electrical properties of the micro-chips have been studied. Our results show that sidewall surface morphology and optical and electrical properties of the micro-chips degrade with increased beam current. After potassium hydroxide etching with different times, an optimal current-voltage and luminescence performance can be obtained. Combining the results of cathodoluminescence mappings and light output-current characteristics, the light extraction efficiency of the micro-chips is reduced as FIB etch depth increases. The mechanisms of micro-square depth on light extraction have been revealed by 3D finite difference time domain. (C) 2018 Optical Society of America

关键词： Aluminum oxide finite-difference time-domain method Light extraction Optical properties Scanning electron microscopy Visible light communications

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