R. Singh, and I. Jose
BITS Pilani Goa Campus
Diffuse Optical Tomography (DOT) uses Near Infra-red (NIR) light to monitor physiological changes in internal organs. NIR light being less energetic in nature can be used for continuous monitoring of tumor infected biological tissue, neonatal brain and many such applications where high energy radiation can cause severe damage. The forward problem of DOT, which involves obtaining of the ...
Y. Pennec, Y. El Hassouani, C. Li, B.D. Rouhani, E.H. El Boudouti, H. Larabi, and A. Akjouj
Institut d’Electronique, de Microélectronique et de Nanotechnologie, Université de Lille, Villeneuve d’Ascq, France
Phononic crystals are a class of materials that exhibit periodic variations in their density and elastic properties. Such crystals modify the propagation of acoustic waves and prohibit the propagation of sound for frequencies within the band gap. We discuss the simultaneous existence of phononic and photonic band gaps in a periodic array of silicon pillars deposited on a homogeneous SiO2 ...
L. M. Hayden, D. A. Sweigart
Department of Physics, University of Maryland Baltimore County, Baltimore, MD, USA
The generation of terahertz frequency radiation (0.1-10 THz) is an important technological goal due to the use of this non-ionizing radiation to penetrate a wide range of non-conducting materials. One outstanding problem has been the propagation of THz radiation in guided wave devices. Few studies on the construction of efficient THz waveguide devices have been performed. We designed and ...
吴强 , 潘崇佩 , 张琦 ,
“极化激元”是固体物理学中的重要概念，泛指各种极性元激发与光子的耦合。其中，声子极化激元是指晶格振动的声子与电磁场中的光子相互耦合的一种极化激元波。使用飞秒光在铁电晶体铌酸锂中通过光学非线性效应可产生声子极化激元，其频率位于太赫兹波段，在晶格的振动弛豫、太赫兹光谱、与介观微结构作用等领域已有广泛应用。 声子极化激元涉及电磁场和晶格场的耦合问题，其形式满足黄昆方程。我们使用 COMSOL Multiphysics® 的多物理场（偏微分方程组以及射频模块）模拟了块状铌酸锂晶体中产生声子极化激元波的产生和传输。 铌酸锂晶体作为太赫兹应用的集成化平台，可通过在平板波导上引入微结构实现对太赫兹波的调控。诸多手段中，太赫兹天线作为电磁场的传播场与局域场转换的关键部件，对太赫兹通信和太赫兹光谱等领域都有不可替代的作用。基于这一点，我们设计了一种尖端相对的棒状天线结构，使用 COMSOL ...
A. Pors, O. Albrektsen, S.I. Bozhevolnyi, and M. Willatzen
Mads Clausen Institute, University of Southern Denmark, Sønderborg, Denmark
Institute of Sensors, Signals and Electrotechnics, University of Southern Denmark, Odense, Denmark
The use of plasmonic effects to dramatically enhance the electromagnetic field near the surface of a metallic nanostructured surface has grown into a large research area in the effort to take advantage of the surface enhanced field. In this paper the electromagnetic field near a nano-sized truncated spherical cavity embedded in a gold substrate is investigated and modeled in 3D with COMSOL ...
Determination of the Optical Properties of Individual Gold Nanorods through Numerical Modeling and Experiment
Y. Davletshin, J.C. Kumaradas
Ryerson University, Toronto, ON, Canada
The optical scattering and absorption of gold nanorods (GNRs) depends on its size, shape, and surroundings. This dependence is due to both intrinsic and extrinsic effects. A good understanding of this dependence is needed for applications of GNRs in photo-thermal therapy, optical and opto-acoustic imaging, biosensing, and other photonic areas. Extrinsic effects are caused by the production of ...
庾金涛 , 李清灵 , 房陈岩 ,
随着我国国民经济的持续高速发展，生活与生产的用电量越来越大，电力行业的规模日益增大。电力设备在不正常工作时，大多会产生电弧电晕，通过检测电晕电弧等目标，就可以获知电力系统设备的损害程度。然而，目前并没有对真实的电弧电晕目标进行非光子计数方式的定量化研究。本文作者研制了一套紫外外波段的面阵成像探测系统，对实验室人工制造的高电压电弧电晕目标进行了相关的分析与实验研究。 利用 COMSOL Multiphysics® 的等离子体物理场接口的 DC 放电接口，对实验所用的天梯仪器的放电行为建模，分子碰撞数据选择大气压下的空气模型，对电晕放电辉光主要贡献的成分N2+，进行密度分布计算，结果换算成光强，得到定性的光强分布，与相机拍摄结果对比。 自制的一套紫外面阵成像系统，对由实验室高压设备在空气中产生的电弧电晕目标开展了紫外成像实验，对电弧电晕目标在 200-1000nm ...
I. Lancranjan and C. Gavrila
Advanced Study Centre, National Institute for Aerospace Research “Elie Carafoli”, Bucharest, Romania
Technical University of Civil Engineering Bucharest, Bucharest, Romania
Laser anemometers based on application of Doppler Effect have been developed and are used in-flight, on aircrafts for measurement of air flow parameters, mainly its speed versus the airplane. The air speed measurements are vital for safe flights. The main basic idea of Doppler techniques consists in measuring the frequency of scattered light. In this paper, we propose a study of a laser Doppler ...
D. Grabovi?ki?, J.C. González, P. Benítez, J.C. Miñano
Cedint Universidad Politécnica de Madrid, Madrid, Spain
Negative Refractive Lens (NRL) has shown that an optical system can produce images with details below the classic Abbe diffraction limit. This optical system transmits the electromagnetic fields, emitted by an object plane, towards an image plane producing the same field distribution in both planes. Recently, two devices with positive refraction, the Maxwell Fish Eye lens (MFE) (Leonhardt et al. ...
李学识 , 郑李娟 ,
A patch antenna based on metamaterials of composite split-ring-resonators (CSRRs) and strip gaps is designed with COMSOL Multiphysics® software. The antenna is constructed by using CSRR structures in forms of circular rings on the patch and employing strip gaps on the ground plane. The signal is fed by a common microstrip line that connects the patch and the input port. The antenna is based on a ...