共查询到19条相似文献,搜索用时 0 毫秒
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研究了完全各向异性超常材料中的倒退波传播现象,得到了在材料本征轴和传输轴成任意角度情形下倒退波形成的条件,分析了超常材料的介电张量和磁导率张量、电磁波的偏振方式对倒退波形成和传播的影响. 在此基础上,进一步分析了几种不同色散曲线关系的各向异性超常材料中倒退波的产生情况,获得了电磁波波矢和坡印亭矢量(能流)夹角的具体表达式和倒退波传播的一般性结论. 此外,还研究了近零介电常数超常材料中倒退波的传播特性,发现在此类超常材料中倒退波只能是完美倒退波.
关键词:
超常材料
负折射
倒退波
各向异性 相似文献
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研究了由左手材料、负介电材料、常规介电材料所构成的几种五层对称结构表面等离子体激元的特性.讨论了表面等离子体激元的存在区域、色散关系、以及p和s偏振的表面色散曲线枝,发现表面模的性质强烈依赖于系统的组成材料及其组合方式|层数越多,表面色散曲线枝也越多,处在频率通带的表面极化模态也越多|在五层结构中有p和s两种偏振的表面等离子体激元,在共振时,可导致p波和s波强透射.此外,通过使用衰减全反射方法,探讨了激发并观察表面等离子体激元的可能性. 相似文献
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当电磁波的传输轴和各向异性超常介质的光轴成任意夹角时,发现在界面处可以产生反常全向全反射和反常负折射现象.导出了电磁波的入射角和能流折射角之间的函数关系,根据此关系可方便地选择合适的介电张量和磁导率张量,使特定入射角所对应的折射是正或是负.此外,发现当入射角小于某一角度时,尤其在垂直入射附近时,透射率最小甚至为零;基于这一特性,提出了一种新型的薄片型高通空间滤波器的构想,和传统的空间滤波系统相比,可以大大减少滤波系统的体积;这一特性也可用于构造空间低频反射器件.
关键词:
超常介质
各向异性
反常传播
空间滤波 相似文献
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We construct an incident-direction-selective transmission filter based on anisotropic metamaterial, and explore the possibility of complete tunneling when elements of permittivity and permeability tensors of the anisotropic metamaterial are totally or partially negative. We first deduce the expressions of field distribution, reflection and transmission amplitudes in our filter and then study the influence of anisotropic metamaterial on the tunneling incident angle of light, including seven subcases of different combinations of positive and negative permittivity and permeability components. At last we conclude the principle of appearance of complete tunneling. 相似文献
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A mixed-structure form of one-dimensional metamaterial structure composed of single negative permittivity material and anisotropic metamaterial has been investigated in this paper. Such a multi-layer metamaterial structure constitutes special resonant structures, which can be used to control wave propagation and realize the complete separation of TM and TE wave by choosing specific parameters. Theoretical analysis and numerical calculations have been performed to confirm the above results. Specifically, augments in incident angles of TM and TE waves make complete transmission frequencies right shift, and the thicknesses of this resonant structure determine propagation modes and propagation frequencies. 相似文献
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Jie Luo Ping Xu Tingting Sun Lei Gao 《Applied Physics A: Materials Science & Processing》2011,104(4):1137-1142
The dispersion characteristics of one-dimensional heterostructure with metamaterial is presented. We give a theoretical analysis
and numerical simulations for tunable beam splitting and negative refraction. By adjusting the lattice constant of the heterostructure
or the permeability of the metamaterial, the splitting angle can be tuned. Interestingly, if both the average permittivity
and permeability are zero, the splitting angle will be 180 degrees. Moreover, when the permeability of metamaterial is small
enough, the light cannot propagate in the heterostructure if the incident angle is less than the critical angle. And as soon
as the incident angle is larger than the critical angle, negative refraction will occur. In addition, the negative refraction
can also be tuned. 相似文献
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The polarization-sensitive propagation in the anisotropic metamaterial (AMM) with double-sheeted hyperboloid dispersion relation is investigated from a purely wave propagation point of view. We show that TE and TM polarized waves present significantly different characteristics which depend on the polarization. The omnidirectional total reflection and oblique total transmission can occur in the interface associated with the AMM. If appropriate conditions are satisfied, one polarized wave exhibits the total refraction, while the other presents the total reflection. We find that the opposite amphoteric refractions can be realized by rotating the principle axis of AMM, such that one polarized wave performs the negative refraction, while the other undergoes positive refraction. The polarization-sensitive characteristics allow us to construct two types of efficient polarizing beam splitters under certain achievable conditions. 相似文献
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基于麦克斯韦旋度方程, 将磁电超材料板中的电元件和磁元件分别等效为面电流和面磁流, 通过计算这些周期性面电流和面磁流在某个磁电超材料板上产生的总电场和总磁场, 获得了关于面磁流密度和面电流密度的两个方程, 进而推导出了周期性磁电超材料折射率与磁元件的磁导率、 电元件的介电常数和空间色散项之间关系的解析公式. 与传统的折射率计算公式不同, 该解析公式充分考虑到了空间色散以及磁电超材料的电元件和磁元件的相互作用. 折射率理论曲线和基于仿真实验数据的提取值曲线能很好地符合, 这说明文中推导的折射率公式能够正确地描述磁电超材料的负折射特性. 本文的结果将为分析电磁元件之间的相互作用以及设计负折射率符合一定要求的磁电超材料提供重要的理论参考.
关键词:
磁电超材料
周期性结构
负折射率 相似文献
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基于树枝结构单元思想,提出了光频三维各向同性左手超材料球刺结构单元模型.采用金属的Drude原理,运用等效媒质理论,仿真研究了结构的电磁响应特性.在晶格间距与工作波长的比值满足等效媒质理论要求的前提下,通过调节结构单元的几何参数,发现它能在光波段出现介电常数和磁导率同时为负值的区域,实现折射率小于零的左手超材料响应特性.该模型结构简单,具有各向同性特点.研究结果为采用"由下向上"方法制备光波段的三维左手超材料指出了新的途径.
关键词:
球刺模型
光波段
三维
各向同性 相似文献
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We investigate the wave propagation in an anisotropic metamaterial with single-sheeted hyperboloid dispersion relation. Based
on boundary conditions and dispersion relations, we find that the opposite amphoteric refraction, such that E (or H)-polarized
waves are positively refracted whereas H (or E)-polarized waves are negatively refracted, can occur at the interface associated
with the anisotropic metamaterial. Under a certain condition, both E- and H-polarized waves can exhibit the same single-sheeted
hyperboloid or straight line dispersion relation, while the two polarized waves exhibit different propagation characteristics.
We expect some potential device applications can be derived based on the unique amphoteric refraction properties.
PACS 78.20.Ci; 41.20.Jb; 42.25.Gy 相似文献
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Francisco Javier González 《Optics Communications》2011,284(5):1429-1434
In this work the resonance, frequency response, and far-field patterns of an optical nano-antenna placed on an interface between air and a metamaterial substrate is obtained through finite element calculations. The metamaterial is characterized by an effective, macroscopic index of refraction which can take negative and near-zero values, or by published values of the effective permittivity and permeability for metamaterials. The results show that the resonant wavelength and response can be fitted to analytical functions that are even functions of the index of refraction, this is consistent with the knowledge that negative indices of refraction allows for wave propagation in the same magnitude but opposite direction observed with positive indices of refraction. The simulations also show that substrates with near-zero index of refraction will enhance the antenna response by 62% compared to substrates with n > 1. Lossy metamaterials are also considered in the simulations. The far-field pattern of the antenna, obtained through a near-field to far-field transformation, behaves the same independently of the sign of the index of refraction, also the far-field pattern for the emission towards near-zero substrates is nearly constant and independent of the angle for the evaluated angular range. 相似文献
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We present a theoretical study of the propagation properties of polarized photons passing through the cavity with an anisotropic metamaterial. We find that the resonant peaks of transmission appear for photons polarized in a certain direction corresponding to a negative element of the permittivity tensor. This indicates the potential for applying such cavity structures as filters for photons with certain polarizations. The resonant peak of transmission for photons having a given frequency can be achieved by adjusting the thicknesses of the air and metamaterial. If the frequency of the incident photons and the thickness of the metamaterial are fixed, the cavity structure can be used as a photon switch controlled by the thickness of the air. The effect of the absorption is considered, and the result shows that the transmission peak always appears, even for metamaterials with large absorption. Finally, the polarization manipulation of such structures is explored. 相似文献