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1.
通过在金属表面刻成浅的垂直凹槽,并在槽内填充不同的介质,对金属表面浅槽周期结构上传播的表面等离子体激元的色散特性与填充介质的关系进行了研究.研究表明通过在周期凹槽内填充介质可以有效降低人工表面等离子体激元的渐近频率,并增强金属表面对电磁场的约束.分析了太赫兹波段金属的吸收损耗对人工表面等离子体激元特性的影响,结果显示基于填充介质的浅槽周期表面结构可以获得长距离传输以及场的亚波长约束.通过对波传输的数值仿真,验证了该表面结构在太赫兹波段良好的导波能力.这种表面结构对太赫兹波段新型集成导波器件的设计具有参考价值.  相似文献   

2.
张学进  陆延青  陈延峰  朱永元  祝世宁 《物理学报》2017,66(14):148705-148705
作为束缚于表面或界面的电磁波与极性元激发的耦合模量子,表面极化激元是克服衍射极限的核心物理.在紫外、可见以及近红外波段,表面等离子极化激元展现出了亚波长特性,具有高分辨成像等应用,并发展成为"表面等离子极化激元亚波长光学"学科;在中红外波段,表面声子极化激元发挥着同样的作用.太赫兹波段曾是人类认识的空白区域,近三十年来得以高速发展,其战略意义重大.具有克服衍射极限能力的太赫兹表面极化激元同样是小型化与集成化太赫兹器件,以及太赫兹超高分辨成像的重要物理基础.近几年来,对以石墨烯为代表的二维材料的研究突飞猛进,诞生了"石墨烯表面等离子极化激元亚波长光学"这门学科,并贡献于太赫兹领域.本文对可在太赫兹波段工作的人工超构材料、掺杂半导体、二维电子气、二维材料、拓扑绝缘体等结构材料的表面极化激元进行了较为全面的总结与介绍,为研制克服衍射极限的太赫兹集成光子学器件提供可资借鉴的物理基础.  相似文献   

3.
陈泳屹  秦莉  佟存柱  王立军 《物理学报》2013,62(16):167301-167301
表面等离子体可以将光子局域在金属表面附近, 并形成很强的近场能量密度, 可以大大提高金属表面附近分子的发光效率和光电转换吸收材料的利用率, 从而提高发光器件和光电转换器件的效率. 本文研究了在一维周期性金属-介质混合结构的光栅中表面等离子体激元的耦合条件, 给出了耦合效率随着结构和填充因子的变化, 并证明了在光栅的填充因子较高以至光栅的金属间隔较小时, 光子耦合成为表面等离子体的效率较高, 可以达到94%以上. 关键词: 表面等离子体激元 填充因子 光栅 吸收光谱  相似文献   

4.
王玥  贺训军  吴昱明  吴群  梅金硕  李龙威  杨福杏  赵拓  李乐伟 《物理学报》2011,60(10):107301-107301
在获得太赫兹波段碳纳米管薄膜的介电特性基础上,利用数值THz时域光谱技术研究了碳纳米管薄膜栅周期结构的表面等离子激元的传播特性和局域化现象. 研究结果表明,在栅周期为168 μm时,频率在0.5-2.5 THz之间出现两个等离子模式的共振峰值,分别位于0.99 THz和1.95 THz,这与理论计算结果相符合. 数值计算的表面等离子激元传播距离与理论预测值相一致,达到了146 μm. 此外,分析了栅厚度与栅宽度变化对表面等离子波特性的影响. 关键词: 太赫兹 碳纳米管 表面等离子波  相似文献   

5.
设计了褶皱石墨烯波导结构激发表面等离子体激元,通过设计周期阵列结构实现了表面等离子体激元传播损耗的补偿.理论分析了周期阵列结构的表面等离子体激元传播模型和补偿损耗的方式,结果表明褶皱衍射激发表面等离子体激元波导不仅能够激发表面等离子体激元,还能利用表面等离子体激元波矢关系实现器件参数控制,周期阵列增益全程补偿损耗的方式可以显著增加表面等离子体激元的传播距离.数值分析结果进一步表明:该结构具备了保持亚波长尺寸的强局域化优势;周期阵列增益全程补偿可以显著提高纳米腔中的电场强度,降低传输损耗;波导结构的粒子反转水平较高,自发辐射噪声的扰动较低.设计的石墨烯波导器件可以为微纳光学集成、光子传感和测量等领域提供理想的亚波长光子器件.  相似文献   

6.
设计了褶皱石墨烯波导结构激发表面等离子体激元,通过设计周期阵列结构实现了表面等离子体激元传播损耗的补偿.理论分析了周期阵列结构的表面等离子体激元传播模型和补偿损耗的方式,结果表明褶皱衍射激发表面等离子体激元波导不仅能够激发表面等离子体激元,还能利用表面等离子体激元波矢关系实现器件参数控制,周期阵列增益全程补偿损耗的方式可以显著增加表面等离子体激元的传播距离.数值分析结果进一步表明:该结构具备了保持亚波长尺寸的强局域化优势;周期阵列增益全程补偿可以显著提高纳米腔中的电场强度,降低传输损耗;波导结构的粒子反转水平较高,自发辐射噪声的扰动较低.设计的石墨烯波导器件可以为微纳光学集成、光子传感和测量等领域提供理想的亚波长光子器件.  相似文献   

7.
李巍  王永钢  杨伯君 《物理学报》2011,60(2):24203-024203
表面等离子体激元是金属表面电子集体振荡,它以波的形式在金属和介质之间的界面中传播.近期Huck等证明等离子体激元可以处在压缩态,本文利用量子光学的热库理论,研究金波导损耗对表面等离子体激元压缩态的影响,并对Huck等的实验结果给与理论解释. 关键词: 表面等离子体激元 压缩态 热库理论  相似文献   

8.
对通过棱镜耦合的太赫兹表面等离激元共振传感器的工作特性进行了理论分析.此类器件在可见光波段工作时,在由样品折射率、金属膜层性质和厚度决定的共振角度下会出现一个反射极小峰;但工作在太赫兹频率时,表面等离激元共振现象表现为一个反射增强的尖峰,而且这一共振角度与棱镜和样品的折射率之间存在一个简单的对应关系,并不依赖于棱镜所镀...  相似文献   

9.
胡海峰  蔡利康  白文理  张晶  王立娜  宋国峰 《物理学报》2011,60(1):14220-014220
本文根据锑化铟(InSb)材料在THz波段下复介电常数对温度的响应特性,采用了带有光栅的锑化铟-介质-锑化铟的表面等离子体波导结构,实现了1THz频率光束的准直出射,并能够通过调整结构两侧光栅的温度差来控制出射光束的角度.由时域有限差分方法得到光束偏转角度与温度差之间的关系.理论上利用表面等离子体波导模式的光栅耦合机理解释光束方向改变的原因. 关键词: 表面等离子体 太赫兹 时域有限差分方法 光束方向控制  相似文献   

10.
高春梅  陈麟  谢乐  彭滟  陈克坚  蔡斌  朱亦鸣 《光子学报》2012,41(10):1156-1160
为研究不同周期数的牛眼结构对太赫兹透射的影响,本文利用微机械加工方法,在铝板上分别制作5个圆环凹槽和15个圆环凹槽两种牛眼结构,并利用时域太赫兹波谱系统,对比了这两种不同周期数的牛眼结构的太赫兹时域信号和频域信号.实验结果显示,0.1~2.7THz宽频太赫兹参考信号可以被两种不同周期数的牛眼结构滤成窄带信号,中心峰值均在约0.53THz处,在该值处,5个圆环凹槽的透射率约为55.7%,15个圆环凹槽的透射率约为68.3%,1THz以上高频信号都被基本滤除,小周期数样品与大周期数样品太赫兹透射谱信号带宽与幅值的差别主要是由于周期性展开不足及边缘泄漏所引起.本文利用伪表面等离子理论解释了滤波效果,并通过有限元方法模拟仿真了宽频太赫兹信号通过不同周期数的牛眼结构后的样品信号,模拟结果与实验结果符合得较好,证实了不同周期数的牛眼结构对太赫兹电磁波的增透效应是不同的.  相似文献   

11.
In this paper, we investigate numerically the characteristics of surface plasmon polaritons (SPPs) sustained by two-dimensional arrays of metallic pillars protruding out of planar metal surfaces at terahertz (THz) frequencies. Various shapes of the pillars are analyzed, and it is shown that the pillar shape only has weak influence on the dispersion of spoof SPPs. However, the loss of spoof SPPs is closely dependent on the pillar shape. It is also shown that spoof SPPs on textured surfaces with pillars can exhibit much better confinement than those on pierced surfaces with holes.  相似文献   

12.
In this Letter we develop a theory of spoof plasmons propagating on real metals perforated with planar periodic grooves. Deviation from the spoof plasmons on perfect conductor due to finite skin depth has been analytically described. This allowed us to investigate important propagation characteristics of spoof plasmons such as quality factor and propagation length as the function of the geometrical parameters of the structure. We have also considered THz field confinement by adiabatic increase of the depth of the grooves. It is shown that the finite skin depth limits the propagation length of spoof plasmons as well as a possibility to localize THz field. Geometrical parameters of the structure are found which provide optimal guiding and localization of THz energy.  相似文献   

13.
We present a comprehensive experimental study of terahertz (THz) wave propagation utilizing surface plasmon polaritons (SPPs) on the interfaces of a thin dielectric core layer sandwiched between two corrugated metallic claddings. THz wave impinges on the structured surfaces at normal incidence. Long-lasting oscillation propagation features are observed in the temporal waveform after traveling through the periodic arrays. The enhanced THz transmission can be achieved due to the coupling between incident waves to SPPs at the bottom and top interfaces. The finite element method is used to simulate the field distribution and the transmission mode in the waveguide. The hybrid waveguide with low absorption has great potential applications in THz integrated devices.  相似文献   

14.
In this Letter, we show how the dispersion relation of surface plasmon polaritons (SPPs) propagating along a perfectly conducting wire can be tailored by corrugating its surface with a periodic array of radial grooves. In this way, highly localized SPPs can be sustained in the terahertz region of the electromagnetic spectrum. Importantly, the propagation characteristics of these spoof SPPs can be controlled by the surface geometry, opening the way to important applications such as energy concentration on cylindrical wires and superfocusing using conical structures.  相似文献   

15.
A dielectric-coated metal wire with an intervening air gap between the conductor and inner surface of the dielectric is presented and demonstrated by theoretical calculation at terahertz frequencies. The characteristic equation of such a modified Goubau surface-wave transmission line is derived for the general case of a lossy dielectric and imperfect conductor. The terahertz attenuation of the modified Goubau line is investigated by using the accurate classical relaxation-effect frequency dispersion model. The influences of the different dimensions, different metal and dielectric materials on terahertz attenuation are also analyzed. In addition, the errors introduced by adopting the traditional and much simpler classical skin-effect model are also quantified. By using various conductivity models, the variation of the conductor loss is changed from 2.8% to 5.5%, and the variation of total loss is changed from 2.4% to 4.7%. It is shown that for certain combinations of the electrical dimensions of the structure the improvement in the attenuation constant over the Goubau line can be higher than 5 dB and realize stronger field confinement at terahertz frequency. The numerical results are very useful for the development of the surface plasmon polaritons (SPPs) devices in the fields of terahertz spectroscopy, sensors and detectors.  相似文献   

16.
Complementary metal structures manifest a remarkable scattering feature, known as Babinet's principle. Meanwhile, for surface modes confined to one or two dimensions, the relation between the modes on complementary structures has not been thoroughly studied. Here, spoof surface plasmon polaritons supported on complementary metal films are systematically investigated. The duality of electromagnetism guarantees that these surface modes on complementary metal films possess precisely the same dispersion regardless of the geometry of the grooves, which is confirmed by both numerical simulations and experimental measurements. This work may open another avenue for spoof surface plasmon polaritons in both the theoretical and practical aspects.  相似文献   

17.
基于金属表面等离子激元控制光束的新进展   总被引:2,自引:0,他引:2  
表面等离子激元(Surface plasmon polaritons,SPPs)是一种在金属-介质界面上激发并耦合电荷密度起伏的电磁振荡,具有近场增强、表面受限、短波长等特性,在纳米光子学的研究中扮演着重要角色。近年来表面等离子光学和基于SPPs的纳米光子器件的研究引起了国际上科学家们的广泛关注。讨论了SPPs的基本原理和在亚波长结构下的光学特性,介绍了基于亚波长金属结构的表面等离子激元在空间光束准直与聚焦、平面内光束聚焦与传导和在近场纳米光束的控制等方面的研究情况,以及在纳米光子学器件中的潜在应用。  相似文献   

18.
We report the experimental and theoretical study of the dispersive behavior of surface plasmon polaritons (SPPs) on cylindrical metal surfaces in the terahertz frequency range. Time-domain measurements of terahertz SPPs propagating on metal wires reveal a unique structure that is inconsistent with a simple extrapolation of the high frequency portion of the dispersion diagram for SPPs on a planar metal surface, and also distinct from that of SPPs on metal nanowires observed at visible and near-infrared frequencies. The results are consistent with a numerical solution of Maxwell's equations, showing that the dispersive behavior of SPPs on a cylindrical metal surface at terahertz frequencies is quite different from that of SPPs on a flat surface. These findings indicate the increasing importance of skin effects for SPPs in the terahertz range, as well as the enhancement of such effects on curved surfaces.  相似文献   

19.
We demonstrate a physical mechanism for terahertz(THz) generation from surface plasmon polaritons(SPPs). In a structure with a bulk Dirac semimetals(BDSs) film deposited on a dielectric substrate, the energy of the asymmetric SPP mode can be significantly enhanced to cross the light line of the substrate due to the SPP-coupling between the interfaces of the film. Therefore, the SPPs can be immediately transformed into Cherenkov radiation without removing the wavevector mismatch. Additionally, the symmetric SPP mode can also be dramatically lifted to cross the substrate light line when a buffer layer with low permittivity relative to the substrate is introduced. In this case, dual-frequency THz radiation from the two SPP modes can be generated simultaneously. The radiation intensity is significantly enhanced by over two orders due to the field enhancement of the SPPs. The radiation frequency can be tuned in the THz frequency regime by adjusting the beam energy and the chemical potential of the BDSs. Our results could find potential applications in developing room temperature, tunable, coherent, and intense THz radiation sources to cover the entire THz band.  相似文献   

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