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在理论分析的基础上,结合实验研究了单负材料/正折射率材料(或单负材料)/单负材料三明治结构的电磁隧穿性质.这种结构的电磁隧穿来源于入射平面波与结构的表面或体极化激元的耦合,从理论上讨论并计算了正入射情况下这种结构中的极化激元的色散关系.发现:由单负材料作为边界而正折射率材料为中间层的三明治结构具有体极化激元,这种极化激元的共振频率随着中间层厚度的增加向低频移动;由不同性质的单负材料构成的三明治结构具有两条色散曲线,这两条色散曲线随着中间层厚度的增加而简并.随后基于L-C传输线技
关键词:
单负材料
极化激元
隧穿
L-C传输线')" href="#">L-C传输线 相似文献
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含负折射率材料的Thue-Morse序列结构的光学透射谱 总被引:5,自引:5,他引:0
讨论了由正折射率材料和具有色散的负折射率材料构成的Thue-Morse序列结构的透射谱,用传输矩阵元的递推关系式计算透射率.数值计算结果表明,这种系统存在一个n=0带隙,它与Bragg带隙相比,对入射角变化和电场偏振方向的变化更不敏感.此外,带隙的位置不随序列阶数的不同而变化.同时,对TM序列结构完全透射态的场分布进行了研究,发现光强的分布具有与晶格结构相似的分布. 相似文献
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基于有效介质理论研究了石墨烯/介质周期结构的电磁性质, 研究发现这种复合结构的等频面在太赫兹和远红外波段为双曲线, 可用来实现石墨烯基双曲色散特异材料. 通过改变石墨烯的费米能级、介质层厚度和单元结构中石墨烯的层数, 可很容易地调节双曲色散存在的频段. 由于等频面的双曲色散特性, 石墨烯基双曲色散特异材料在远低于截止频率的范围内, 对斜入射的电磁波具有负的能量折射率和正的相位折射率, 并支持局域体等离子体模式. 基于衰减全反射结构, 研究了体等离子体的激发, 探索了体等离子体在可调的光学反射调制器中的应用. 相似文献
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作为一种特殊的光学现象,对一定的光学结构,Goos-H?nchen(GH)位移与构造材料密切相关.对电介质/超导/电介质这一结构,本文给出了GH位移在超导材料为近零折射率材料时随入射角、光波长和超导层厚度等参数的变化曲线.结果表明,GH位移随上述参数的变化规律,与超导材料折射率为零时的波长(阈值波长)相关联,波长大于和小于阈值波长时的变化规律存在一定的差异.近零折射率材料在光子学领域具有广泛的应用.计算结果为新型光子学器件研究开发提供了参考.论文对大学生理解近零折射率概念,以及近零折射率区超导材料的Goos-H?nchen位移也有所帮助. 相似文献
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白光在LiNbO3∶Fe晶体中写入的任意折射率分布光波导 总被引:3,自引:3,他引:0
在理论分析LiNbO3∶Fe晶体中光致折射率变化分布与写入光的强度分布之间关系的基础上,提出了一种在该晶体中写入具有任意折射率分布光波导的新方法.利用由白光经电寻址空间光调制器得到的强度分布不同的片光辐照晶体,分别写入了折射率呈误差函数分布和平方律分布的光波导结构.采用干涉法测量了晶体中的光致折射率变化,并用推导出的折射率变化分布解析表达式很好地拟合了测量数据.实验结果表明,该方法是可行的.利用白光光源结合高分辨率的空间光调制器有望在多种光折变材料中制备出具有任意折射率分布的高质量光波导. 相似文献
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通过对左手材料的理论分析,设计了一种宽频带左手材料结构单元.该结构单元由一个矩形闭合环和十字型结构构成的谐振器和金属线组合而成.这种新结构中的谐振器实现负磁导率,金属线实现负介电常量,经过合理的设计,可以在某一频段内使得磁导率和介电常量同时为负,即具有负的有效折射率和正的波阻抗.数值仿真结果表明:在其工作频段内存在一个通带并且在17.6~29.0 GHz频率范围内折射率实部为负,而虚部接近于零;同时在该频率范围内波阻抗实部大于零,从而说明了该左手材料具有左手特性.除此之外,相对左手带宽达到48.9%,远远优于传统的左手材料. 相似文献
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通过对左手材料的理论分析,设计了一种宽频带左手材料结构单元.该结构单元由一个矩形闭合环和十字型结构构成的谐振器和金属线组合而成.这种新结构中的谐振器实现负磁导率,金属线实现负介电常量,经过合理的设计,可以在某一频段内使得磁导率和介电常量同时为负,即具有负的有效折射率和正的波阻抗.数值仿真结果表明:在其工作频段内存在一个通带并且在17.6~29.0GHz频率范围内折射率实部为负,而虚部接近于零;同时在该频率范围内波阻抗实部大于零,从而说明了该左手材料具有左手特性.除此之外,相对左手带宽达到48.9%,远远优于传统的左手材料. 相似文献
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Russian Physics Journal - The concept of the negative refractive index with application to doubly negative metamaterials is critically analyzed. The positive value of the refractive index is... 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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We have numerically demonstrated chiral metamaterials based on double-layered asymmetric U-shape split ring resonators. Dual-band circular dichroism is found in the whole frequency regime from 50 to 250 THz by studying the transmission properties. Huge optical activity and the induced negative refractive index are obtained at resonance by calculating the optical activity and ellipticity of the transmitted E-fields. Chirality parameter and effective refractive index are retrieved to illustrate the tunable optical properties of the metamaterials. The underlying mechanisms for the observed circular dichroism are analyzed. These metamaterials would offer flexible electromagnetic applications in the infrared regime. 相似文献
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《中国光学快报(英文版)》2020,(6)
Refractive index enhancement is crucial in the fields of lithography, imaging, optical communications, solar devices, and many more. We present a review of advancements in the process of designing high refractive index metamaterials, starting from quantum coupling and photonic bandgap materials to metamaterials utilizing deep subwavelength coupling to achieve ever-high values of refractive index. A particular attention is given to experimentally verified schemes in engineering a high index of refraction. The understanding of the evolution of material design from intrinsic electronic states manipulation to meta-atoms design is not only fascinating but also a prerequisite to developing successful devices and applications. 相似文献
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《Current Applied Physics》2014,14(4):570-574
We report on the effect of dielectric substrate on the resonance shift of metallic metamaterials operating in the terahertz frequency region. The resonance frequencies for various metamaterials obtained by time-domain spectroscopy agree well with calculations based on the finite-difference time-domain method. The dependencies of the resonance frequency to substrate index are studied, and are systematically determined by introducing an effective substrate index. The relative contributions of the substrate index for various metamaterials are obtained by fitting the numerically obtained effective refractive indices as a function of substrate index, which is found to be ∼0.63 regardless of the metamaterial geometry. 相似文献
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《Photonics and Nanostructures》2014,12(3):231-238
Phase space analysis of light refraction in optical systems consisting of slabs or thin lenses from either metamaterials with negative refractive indices or common materials is performed with the aim of finding the conditions of perfect imaging for metamaterial-based optical systems. The analysis in the paraxial approximation uses ABCD matrices, whereas full ray tracing is employed in the non-paraxial case. The phase space analysis reveals that the ideality of planar metamaterial lenses only occurs when the absolute value of the refractive index in metamaterials is the same as in the surrounding medium. 相似文献
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《Waves in Random and Complex Media》2013,23(4):417-433
AbstractA new method of extracting effective permittivity and permeability of metamaterials has been developed in this paper. Scattering parameters are used to represent effective wave impedance and refractive index of the metamaterials. Considering analytical continuation of effective refractive index of the metamaterials in the upper half of a complex angular frequency plane, a phase unwrapping technique has been implemented to solve branch ambiguity of the refractive index caused by complex inverse cosine function. An empirical formula to estimate the starting frequency in the phase unwrapping technique has been developed to improve the efficiency of the parameter retrieval procedure. Numerical results including five slabs of rods and split-ring resonators (SRRs) and a structure composed of two SRRs and four capacitively loaded strips are given to demonstrate good accuracy, high efficiency, and noise insensitivity of the proposed retrieval method. 相似文献
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Numerical demonstration of three-dimensional terahertz metamaterials based on the causality principle 下载免费PDF全文
A parameter retrieval algorithm based on the causality principle and Kramers-Kronig (KK) relations is employed to calculate the effective parameters of three-dimensional (3D) metamaterials. Using KK relations, the branch selecting problem, which is the challenge of effective parameter retrieval method, can be removed. To reveal the validity of the proposed algorithm, the constitutive refractive index of a homogeneous polymide cube is extracted. The result is in excellent agreement with the intrinsic refractive index of the polymide. Finally, the two terahertz metamaterials with 3D structures are designed and their effective parameters are then retrieved using the proposed algorithm. Numerical simulations are performed using the fuiI-wave electromagnetic solver, CST Microwave Studio. 相似文献
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Hala J. El-Khozondar Rifa J. El-Khozondar Said Zouhdi 《Applied Physics A: Materials Science & Processing》2012,109(4):865-867
The surface wave propagation at the interface between tunable metamaterials (MTMs) and nonlinear media is investigated. Tunable MTMs have a refractive index which can be tuned to negative?Czero?Cpositive values. The nonlinear media are assumed to have a Kerr-like refractive index. The dispersion equation is analytically derived and solved numerically. Results display the different behaviors of the propagating waves as the refractive index is tuned. 相似文献