共查询到19条相似文献,搜索用时 125 毫秒
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二维光子晶体中的缺陷研究 总被引:3,自引:0,他引:3
应用On shell方法研究带缺陷的二维光子晶体 ,缺陷的引入使得原来不透电磁波的禁带中 ,出现了缺陷模 ,即某一频率的电磁波可以透过 ,计算表明缺陷模的频率与透过率随着缺陷的性质及缺陷两边的层数而改变 相似文献
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二维光子晶体中的无序数值模拟研究 总被引:13,自引:0,他引:13
应用on-shell方法研究弱无序情况下的二维光子晶体,无序的引入使得原来不透电磁波的禁带中,出现了共振模,即某一波长的电磁波可以透过,计算结果表明共振模的出现位置,条数多少及透过率随着无序程度的不同而变化。 相似文献
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应用多光子非线性Compton散射模型和有限时域差分法,对Compton散射对磁化等离子体光子晶体缺陷模密温特性的影响进行了理论分析和数值模拟。结果表明,与Compton散射前的情况相比,Compton散射使低温低频处光子禁带中存在缺陷模的明显度降低,缺陷模频率增大,缺陷模和透射率峰值减小;使高温高频处缺陷模和透射率峰值、缺陷模频率显著增大,禁带宽减小,缺陷模位置向高频方向移动。随着电子密度的增大,散射减小了禁带增大效应和缺陷模减小效应,增强了缺陷模频率增大效应;随着电子密度的降低,散射增强了禁带变窄效应、缺陷模峰值增大效应和缺陷模频率减小效应。利用Compton散射,可实现对缺陷模密温特性的有效控制。 相似文献
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二维正方晶格光子晶体禁带特性 总被引:3,自引:3,他引:0
基于平面波展开法,以碳化硅构成二维正方晶格光子晶体,数值模拟了TE模、TM模二维光子晶体的禁带特性,结果表明,TE模更容易形成光子禁带。同时设计了以碳化硅构成二维正方晶格光子晶体波导,数值模拟了TE模、TM模波导的传输特性和禁带特性,结果表明,TE模构成的波导电磁波能够较好的传播,它们的光子禁带都没有出现。研究结论为光子晶体波导器件的开发提供参考。 相似文献
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采用等离子体的分段线性电流密度卷积时域有限差分算法研究了横磁波入射时具有单一线缺陷的二维非磁化等离子体光子晶体的缺陷模特性. 从频域角度分析得到微分高斯脉冲的透射系数,并讨论该光子晶体的晶格常数、介质圆柱半径、周期常数、缺陷层参数和等离子体参数对缺陷模特性的影响. 结果表明,改变周期常数、缺陷层位置和等离子体碰撞频率不会改变缺陷模的频率,改变缺陷层介质圆柱的相对介电常数、半径和缺陷层到介质层的中心距离可以在不改变禁带宽度的前提下实现对缺陷模的调节,改变晶格常数、介质圆柱半径和等离子体频率能同时实现对禁带宽度和缺陷模的调节.
关键词:
等离子体
光子晶体
缺陷模
时域有限差分算法 相似文献
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一维光子晶体掺杂缺陷模研究 总被引:57,自引:9,他引:48
用特征矩阵法计算了光波在包含多种掺杂缺陷的一维光子晶体中的传播规律,与不包含缺陷的结构相比较,在禁带中形成缺陷模。缺陷模的位置、数目和强度不仅和缺陷的产生方式有关,还和缺陷位置处的光学厚度及折射率的变化有关。当掺杂缺陷的位置呈等间距时,相应缺陷模也呈等间距排列。随着掺杂缺陷光学厚度的变化,缺陷模的位置、数目也随之变化。保持掺杂缺陷光学厚度不变,掺杂缺陷折射率的变化将会引起缺陷模强度的变化,并存在一个最大值。缺陷模的出现一般使带隙加宽,尤其是掺杂介质的折射率与周期介质的折射率差别较大时更加明显。掺杂空气介质时可使缺陷模的透射率近似为1。 相似文献
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应用多光子非线性Compton散射模型和分段电流密度卷积时域有限差分法,将入射光和Compton 散射光作为形成缺陷模的机制,研究了Compton散射对具有单一缺陷模的时变磁化等离子体光子晶体缺陷模的影响.结果表明:与Compton散射前相比,入射光频率低于等离子体频率时,禁带中仍存在明显的缺陷模,其频率随等离子体驰豫时间的增大而缓慢增大;等离子体弛豫时间相等时,等离子体均匀分布的禁带透射系数峰值比Epstein分布时小,两者的缺陷模特征都比较明显,但两者的禁带宽度及缺陷模之间的区别明显减小. 相似文献
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Amplitude–frequency characteristics of the transmission coefficient of microwave waveguide photonic crystal with violation of periodicity are studied in the presence of a plane conducting small-size inclusion that occupies a part of the transverse cross section of the waveguide inside a disturbed layer located at different positions. The conducting small-size inclusion in the disturbed layer of photonic crystal causes the low-frequency shift of the defect mode in the band gap, and the maximum shift is observed when the metal inclusion is located at the interface or center of disturbance depending on the thickness of the disturbed layer. 相似文献
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《Chinese Journal of Physics (Taipei)》2018,56(5):2597-2604
In this letter, we introduce a one-dimensional photonic crystal (1DPC) structure with a uniaxial metamaterial defect layer. It is proposed to control the transmitted wave of the defect mode by adjusting the orientation of the optical axis and incidence angle for both polarization states. The 4 × 4 transfer matrix method was employed to calculate the transmittance spectrum of the proposed structure. It is shown that the photonic band gaps, the intensity and the peak wavelength of the defect mode depends on the polarization, the orientation of the optical axis and the incidence angle of the wave, due to the strong anisotropy of the metamaterial. The transmittance spectrum curves at different optical axes of the uniaxial metamaterial and the distinct incidence angles are illustrated graphically. It is shown that the defect mode appears as a peak in the transmission spectrum. Pronounced contrasts in the intensity, wavelength positions of the defect mode and photonic band gap were demonstrated depending on the incidence angle and the orientation of the optical axis of the uniaxial metamaterial defect layer for both polarizations. Our structure offers a great variety of possibilities for designing and controlling the transmitted intensity of the defect mode. 相似文献
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含有多缺陷的一维光子晶体的完全透射及应用 总被引:7,自引:0,他引:7
计算了具有多缺陷且相对中间缺陷具有镜像对称结构的一维光子晶体的透射谱。在光子晶体的禁带中得到了多个完全透射峰且对称性地分布于禁带中心频率两侧。缺陷相距较近时,禁带中心不存在透射峰。所有透射峰都敏感地依赖于中间缺陷的折射率。 相似文献
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《Physics letters. A》2006,351(3):192-197
The polaritonic band structures and transmission spectra of piezoelectric-modulated superlattices are investigated for a variety of supercell configurations. In the absence of a defect layer a polaritonic-like band gap exists and relative band gap can reach as large as 19% for superlattices made of LiNbO3. In the presence of a defect layer, the positions and number of defect modes can be controlled directly by the number of domains in a supercell, the widths of defect modes are determined by layer thickness difference between defect domain and the periodic domain. Such uniformly distributed in-gap modes make them ideal candidates for the potential multiband filters. 相似文献
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利用传输矩阵方法,研究了镜像对称缓变准周期结构一维光子晶体的缺陷模。结果表明,当镜像对称缓变准周期结构一维光子晶体的周期数增加时,禁带宽度逐渐展宽;引入缺陷后,出现缺陷模,缺陷模的波长随缺陷层厚度增加和缺陷层介质折射率的增大而向长波方向移动。 相似文献
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Acoustic wave propagation in a woodpile sonic crystal with a defect is studied theoretically and experimentally. The woodpile sonic crystal is composed of polymethyl methacrylate square rods which orthogonally stacked together, and it is embedded in air background. Defects are created by varying the width and positions of the middle rods in the periodic structure. Defect bands and transmission spectra are calculated by using the finite element method with the periodic boundary condition and the Bloch–Floquet theorem. Frequencies of defect bands are strongly dependent on the width and positions of the middle rods in the periodic structure. The experimental transmission spectra of the woodpile sonic crystals with a defect are also presented and compared with the numerical results. The defect mode properties of the woodpile sonic crystal with a defect can be applied to design novel acoustic devices for filtering sound and trapping sound in defects. 相似文献