共查询到20条相似文献,搜索用时 187 毫秒
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利用传输线技术制备了左手材料,将左手材料与正常材料交替排列组合成平均折射率为零的一维光子晶体.该光子晶体在特定频段具有光子带隙,带隙不随晶格尺度和入射角的变化而改变.通过掺杂技术破坏光子晶体的周期性,可在禁带中引入缺陷模,这种结构的光子晶体可用于实现滤波器小型化和超强耦合.研究表明,通过调节缺陷的厚度可以控制缺陷模的频率,这为调节频率提供了一种方法.实验与仿真结果相符.
关键词:
左手材料
复合左右手传输线
光子晶体 相似文献
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运用Bloch定理和传输矩阵方法,研究了与色散介质毗邻的由两种材料组成的半无限一维光子晶体局域表面态的电场和色散关系.和以空气为背景的一维光子晶体相比,毗邻色散介质的光子晶体表面模色散曲线在一定堆积次序下会在较低的带隙中发生断开,较高带隙中的表面模群速度在不同堆积次序下会有很大差异.当与色散介质毗邻的物质折射率较大时,较高带隙中的表面模群速度较小;与色散介质毗邻的物质折射率较小时,较高带隙中表面模的群速度较大. 相似文献
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对纤芯为左手材料,内包层和外包层都为右手材料的双包层光纤进行了分析.在弱导情况下,且不考虑介质损耗,由亥姆霍兹方程出发,得到了HE、EH、TE和TM导模的色散方程,并在远离截止条件下,对其进行简化.所有的TE和TM模都是简并的.分别讨论了内包层折射率和厚度对该左手材料光纤最低阶导模的影响,画出了各自的色散曲线,并和右手材料光纤导模相应色散曲线进行了比较,发现左手材料光纤的低阶导模具有反常的色散特性. 相似文献
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利用HFSS软件,对电磁波在左手材料中的后向波传输、平板成像特性和近零折射率媒质的定向辐射特性进行了全波仿真研究,分别验证了左手材料与近零折射率媒质的上述特性。利用AnsoftDesigner软件,对去掉并联电感和去掉串联电容的、基于微带线的两种简化的左右手复合传输线构成的具有磁单负和电单负特性介质的电磁特性进行了仿真研究,验证了电磁波在匹配的MNG-ENG介质对结构的隧穿特性。 相似文献
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左手介质矩形波导导模和表面模的场分布 总被引:2,自引:0,他引:2
从麦克斯韦方程组出发,结合电磁场的边界条件,推导出介质矩形波导导模的一般色散方程.对普通介质矩形波导和左手介质矩形波导的导模场分布分别进行了数值模拟.通过对比两种介质矩形波导的导模场分布的模拟结果,发现左手介质矩形波导Ex22模的场分布比普通介质波导Ex00模的场更集中在波导中部.同时,根据处理普通介质矩形波导的Marcatili方法.类比得到左手介质矩形波导表面模的色散方程,并数值模拟了低阶模的场分布,结果表明,能量主要集中在波导的四个角区以及波导的边缘. 相似文献
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Munazza Zulfiqar Ali 《中国光学快报(英文版)》2012,(7):69-72
Wave propagation is studied in structures consisting of alternate left- and right-handed layers.Bragg gap and zero-n gap appear in different frequency regions of the structure.The periodicity of the structure is broken by simply reversing the order of the layers in one half of the structure,resulting in defect modes located inside the zero-n gap and Bragg gap.These modes can be made very narrow by adding more layers in the structure.The defect mode located inside the zero-n gap is sensitive to the symmetry of the structure and insensitive to the angle of incidence of the incoming radiation.Multiple modes are also generated inside the gaps by repeating the structural pattern.Thus,a simple structure can be used for single and multiple modes that are important for different applications. 相似文献
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《中国光学快报(英文版)》2017,(6)
We present an investigation on the propagation properties of the chirped Airy vortex(CAi V) beams through slabs of left-handed materials(LHMs) and right-handed materials(RHMs). We discuss the influence of chirped parameter C on the propagation of the CAi V beams through LHM and RHM slabs. Our simulation results show that a maximum accelerated velocity appears during the propagation process. The intensity concentration of the CAi V beams increases with the absolute value of the chirped parameter. The peak intensity of the CAi V beams changes abruptly, and the chirped parameter plays an active role on the difference of the maximum and the minimum. In the energy flow, we find that the effects of the chirped parameter on the strength of the vortex are different at different propagation distances. 相似文献
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Band rules for the frequency spectra of three kinds of aperiodic photonic crystals with negative refractive index materials 下载免费PDF全文
By means of the theory of electromagnetic wave propagation
and transfer matrix method, this paper investigates the band rules
for the frequency spectra of three kinds of one-dimensional (1D)
aperiodic photonic crystals (PCs), generalized Fibonacci GF(p,1),
GF(1,2), and Thue--Morse (TM) PCs, with negative refractive index
(NRI) materials. It is found that all of these PCs can open a broad
zero-? gap, TM PC possesses the largest zero-? gap,
and with the increase of p, the width of the zero-? gap for
GF(p,1) PC becomes smaller. This characteristic is caused by the
symmetry of the system and the open position of the zero-?
gap. It is found that for GF(p,1) PCs, the possible limit
zero-? gaps open at lower frequencies with the increase of
p, but for GF(1,2) and TM PCs, their limit zero-? gaps
open at the same frequency. Additionally, for the three
bottom-bands, we find the interesting perfect self-similarities of
the evolution structures with the increase of generation, and obtain
the corresponding subband-number formulae. Based on 11 types of
evolving manners Qi(i=1,2,....,11) one can plot out the
detailed evolution structures of the three kinds of aperiodic PCs
for any generation. 相似文献
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Periodic structures consisting of alternating layers of positive-index and negative-index materials have a novel bandgap at the frequency at which the average refractive index is zero. We show that, in the presence of a Kerr nonlinearity, this zero-n gap can switch from low transmission to a perfectly transmitting state, forming a nonlinear resonance or gap soliton in the process. This zero-n gap soliton is omnidirectional, in contrast to the usual Bragg gap soliton of positive-index periodic structures. 相似文献
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Layered heterostructures combining ordinary and negative refractive index materials are shown to display a new type of photonic band gap corresponding to zero (volume) averaged refractive index. Distinct from band gaps induced by Bragg scattering, the zero-n; gap is invariant upon a change of scale length and is insensitive to disorder that is symmetric in the random variable. A metallic structure that exhibits such a band gap is explicitly designed, and its properties are calculated with accurate finite difference time domain simulations. 相似文献
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Lucovsky, Brodsky, Burstein (LBB) have studied the behaviour of mixed crystals by setting up a criterion for the existence
of local mode frequencies in real crystals starting from a diatomic linear chain model. This, while successfully predicting
the one and two mode behaviour for some systems fails to predict the mixed mode behaviour. We propose a similar criterion
for the existence of gap modes, by demanding that the gap mode predicted by the diatomic linear chain model should lie within
the gap of the real three dimensional solid for its existence. It is shown that the gap modes for various systems calculated
using this criterion are in reasonable agreement with the experimental values. The infrared behaviour of mixed crystals has
to be determined by examining the existence of local as well as gap modes for the two end members of the system. This generalized
new criterion successfully predicts the mixed mode behaviour of III–V mixed crystals besides predicting the one and two mode
behaviour, observed in infrared absorption of mixed alkali halioes and III-V compounds. 相似文献