共查询到20条相似文献,搜索用时 15 毫秒
1.
An improved plan-wave expansion method is adopted to theoretically study the photonic band diagrams of twodimensional(2D) metal/dielectric photonic crystals.Based on the photonic band structures,the dependence of flat bands and photonic bandgaps on two parameters(dielectric constant and filling factor) are investigated for two types of 2D metal/dielectric(M/D) photonic crystals,hole and cylinder photonic crystals.The simulation results show that band structures are affected greatly by these two parameters.Flat bands and bandgaps can be easily obtained by tuning these parameters and the bandgap width may reach to the maximum at certain parameters.It is worth noting that the hole-type photonic crystals show more bandgaps than the corresponding cylinder ones,and the frequency ranges of bandgaps also depend strongly on these parameters.Besides,the photonic crystals containing metallic medium can obtain more modulation of photonic bands,band gaps,and large effective refractive index,etc.than the dielectric/dielectric ones.According to the numerical results,the needs of optical devices for flat bands and bandgaps can be met by selecting the suitable geometry and material parameters. 相似文献
2.
Properties of omnidirectional photonic band gap in one-dimensional staggered plasma photonic crystals 总被引:1,自引:0,他引:1
Hai-feng Zhang Shao-bin Liu Xiang-kun KongBo-rui Bian Hui-cao Zhao 《Optics Communications》2012,285(24):5235-5241
In this paper, the properties of the omnidirectional photonic band gap (OBG) realized by one-dimensional (1D) photonic crystals (PCs) with a staggered structure which is composed of plasma and isotropic dielectric layer have been theoretically studied by the transfer matrix method (TMM). From the numerical results, it has been shown that such OBG is insensitive to the incident angle and the polarization of electromagnetic wave (EM wave), and the frequency range and central frequency of OBG can be effectively controlled by adjusting the plasma frequency, the average thickness of plasma layer, the average thickness of dielectric layer and staggered parameters, respectively. The frequency range of OBG can be notably enlarged with increasing the plasma frequency, average thickness of plasma layer, respectively. Moreover, the bandwidth of OBG can be narrowed with increasing the average thickness of dielectric layer. Changing staggered parameters of dielectric and plasma layer means that the OBG can be tuned. It is shown that 1D plasma dielectric photonic crystals (PPCs) with such staggered structure have a superior feature in the enhancement of frequency range of OBG compared with the conventional 1D binary PPCs. This kind of OBG has potential applications in filters, microcavities, and fibers, etc. 相似文献
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In this paper, the properties of anisotropic photonic band gaps (PBGs) for three-dimensional (3D) photonic crystals (PCs) composed of the anisotropic positive-index materials (the uniaxial materials) and the epsilon-negative (ENG) materials with body-centered-cubic (bcc) lattices are theoretically studied by a modified plane wave expansion (PWE) method, which are the uniaxial materials spheres inserted in the epsilon-negative materials background. The anisotropic photonic band gaps (PBGs) and one flatbands region can be achieved in first irreducible Brillouin zone. The influences of the ordinary-refractive index, extraordinary-refractive index, filling factor, the electronic plasma frequency, the dielectric constant of ENG materials and the damping factor on the properties of anisotropic PBGs for such 3D PCs are studied in detail, respectively, and some corresponding physical explanations are also given. The numerical results show that the anisotropy can open partial band gaps in such 3D PCs with bcc lattices composed of the ENG materials and uniaxial materials, and the complete PBGs can be obtained compared to the conventional 3D PCs containing the isotropic materials. The calculated results also show that the anisotropic PBGs can be manipulated by the parameters as mentioned above except for the damping factor. Introducing the uniaxial materials into 3D PCs containing the ENG materials can obtain the larger complete PBGs as such 3D PCs with high symmetry, and also provides a way to design the tunable devices. 相似文献
4.
Shinya Akihiko Notomi Masaya Yokohama Itaru Takahashi Chiharu Takahashi Jun-Ichi Tamamura Toshiaki 《Optical and Quantum Electronics》2002,34(1-3):113-121
Two-dimensional photonic crystals (2D-PhCs) on oxide can be easily incorporated into photonic integrated circuits. Although an asymmetrical structure (air/PhC/oxide) is advantageous in terms of ease of fabrication, it has been pointed out that such a structure may have no photonic band gap (PBG). To clarify the characteristics of the asymmetrical structure, we calculated the band structure using the three-dimensional (3D) FDTD method and measured the transmission characteristics of a fabricated 2D Si-PhC on oxide. The calculations show that we can use a quasi-PBG even in an asymmetrical structure when the PhC thickness satisfies the single-mode condition. The measured transmission characteristics correspond to the calculated band structure and reveal the existence of a quasi-PBG. These results show that the asymmetrical 2D Si-PhC-on-oxide structure can be applied to various optical devices. 相似文献
5.
Kuramochi E. Notomi M. Kawashima T. Takahashi J. Takahashi C. Tamamura T. Kawakami S. 《Optical and Quantum Electronics》2002,34(1-3):53-61
We propose two photonic crystal structures that can be created by combining nanolithography with alternating-layer deposition. Photonic band calculations suggest that a drilled alternating-layer photonic crystal combining two-dimensional (2D) alternating multilayers and an array of vertically drilled holes may achieve a full photonic bandgap. In addition, a 3D/2D/3D cross-dimensional photonic crystal, which sandwiches a 2D photonic crystal slab between three-dimensional (3D) alternating-layer photonic crystals, should provide better vertical confinement of light than a conventional index guiding slab. Fabrication techniques based on existing technologies (electron beam lithography, bias sputtering, and low-pressure ECR etching) require very few process steps. Our preliminary fabrication suggests that, by refining these technologies, we will be able to realize photonic crystals. 相似文献
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A two-dimensional (2D) photonic crystal waveguide in the
\Gamma--K direction with triangular lattice on a
silicon-on-insulator (SOI) substrate in the near-infrared band is
fabricated by the combination of electron beam lithography and
inductively coupled plasma etching. Its transmission characteristics
are analysed from the stimulated band diagram by the effective index
and the 2D plane wave expansion (PWE) methods. In the experiment, the
transmission band edge in a longer wavelength of the photonic crystal
waveguide is about 1590\,nm, which is in good qualitative agreement
with the simulated value. However, there is a disagreement between
the experimental and the simulated results when the wavelength ranges
from 1607 to 1630\,nm, which can be considered as due to the
unpolarized source used in the transmission measurement. 相似文献
8.
The construction of 3D photonic crystals with gaps in the visible or the near-infrared frequency range requires engineering of complex microstructures which are very difficult to realize by etching and micro-fabrication. Consequently, self-ordered systems such as synthetic opals are very promising. Synthetic bare opals are constituted by SiO2 spheres that organize themselves by a sedimentation process in a face centered cubic (fcc) arrangement. Using the plane wave method, we examine the photonic band structures of close-packed opal-based photonic crystals with an SiO2 (n = 1.5) matrix. The incomplete photonic band gaps at the X- and L-points have been studied which correspond to normally incident plane waves onto the (100) and (111) crystal planes. With the transfer matrix method, we model the transmission properties. We find that the incomplete gap at the L-point fully inhibits the transmission of waves propagating in the [111] direction for opal sample thicknesses that are easily obtainable. This property shows that bare opals could be good candidates for complete inhibition of transmission in the near-infrared and visible frequency range for given orientations. 相似文献
9.
基于平面角谱理论,系统研究了BK7玻璃-合金薄膜-空气结构中合金介电常数的变化对反射光自旋霍尔效应的调控规律.数值仿真结果表明,该结构发生表面等离激元共振的共振角主要受合金介电常数实部的影响,随介电常数实部的增加而增大,而虚部对共振角变化的影响相对较小.不同介电常数合金在其共振角处得到的较大光子自旋霍尔效应横移呈集中的带状分布,选取介电常数-2.8+1.6i的Ag-Ni合金时,光子自旋霍尔效应横移能达到1.2×10~5 nm.研究还发现将入射角固定为44.1°时,光子自旋霍尔效应横移随合金介电常数的变化呈轴对称分布,并以最大值为中心呈球面状辐射,离中心点越远光子自旋霍尔效应横移越小.选取介电常数-10.6+1.2i的Ag-Au合金时,光子自旋霍尔效应横移最大能达到8000 nm,相比于以往纯金属纳米结构BK7玻璃-金-空气中得到的最大光子自旋霍尔效应横移3000 nm有了较大的提高.该研究不仅能够有效增强光子自旋霍尔效应,还能为设计等离激元共振传感器等纳米光子器件提供理论依据. 相似文献
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采用Si和SiO2两种介质材料构造一维缺陷光子晶体,缺陷层介质为Si,利用传输矩阵法对带有缺陷的一维光子晶体的传光特性进行了理论分析,并得到其带隙特性.由于缺陷的存在,使得光子晶体的透射谱中产生缺陷峰.当被测温度变化时,根据两种介质的热光效应和热膨胀效应,光子晶体介质和缺陷层的光学厚度和折射率发生变化,透射谱缺陷峰产生漂移,由缺陷峰的中心波长漂移量得到被测温度的大小.构建了一维缺陷光子晶体测量温度的实验系统,实验结果表明缺陷峰中心波长与光子晶体所受的温度呈线性关系,测量灵敏度为0—2
关键词:
温度测量
一维光子晶体
传输矩阵法
缺陷峰 相似文献
11.
周期性受限原子蒸气/电介质层光子带隙(PBG)宽度及其诱导的反射平顶随蒸气层厚度 d的增大而变宽,并在 ( 为原子的共振波长)时达到最大值,之后随d的增大呈变窄趋势. 随着蒸气厚度的增大,带隙的中心频率产生红移,厚度越大,红移量越大. 研究还发现,共振波长处的反射及透射谱具有迪克窄化结构. 这种可调谐的PBGs结构可望用于全光反射镜及滤波器. 相似文献
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周期性受限原子蒸气/电介质层光子带隙(PBG)宽度及其诱导的反射平顶随蒸气层厚度d的增大而变宽,并在d/(λ0/2)=0.5(λ0为原子的共振波长)时达到最大值,之后随d的增大呈变窄趋势.随着蒸气厚度的增大,带隙的中心频率产生红移,厚度越大,红移量越大.研究还发现,共振波长处的反射及透射谱具有迪克窄化结构.这种可调谐的PBGs结构可望用于全光反射镜及滤波器. 相似文献
13.
应用有效折射率微扰法结合二维/三维平面波方法研究了施主和受主缺陷型H1微腔的性质, 使用修正后的有效折射率可以准确地计算微腔的腔模频率, 与三维全矢量时域有限差分法的计算结果很相近. 对于施主型H1微腔, 以介质带边为匹配标准修正的有效折射率计算的微腔腔模频率误差最小, 而对于受主型H1微腔, 匹配标准则应设置为中间带. 有效折射率微扰法既可以将计算的维度从三维降到二维, 大大减少计算所需的计算机内存和时间, 又可以保持计算结果的准确性, 这对于光子晶体微腔的广泛应用具有非常重要的价值. 相似文献
14.
将耦合波导列应用于光子晶体单模波导,提出一种提高光辐射的光子晶体结构. 基于时域有限差分方法的理论研究表明,当将耦合波导列附加到单模光子晶体波导出口端的适当位置,使出射光分成若干强弱不一的光束,这些光束在传播空间通过干涉形成一定程度的汇聚,大大提高了光子晶体波导在水平方向的光辐射效率. 另外,当耦合波导列的行数大于某固定值(2N=8)时,辐射质量基本保持不变,由此可获得最紧凑的器件结构. 这种类型光子晶体在近场光学和集成光学等诸多方面有潜在的应用价值.
关键词:
光子晶体波导
光辐射
波导列
耦合波导 相似文献
15.
利用传输矩阵方法研究了掺杂半导体n-GaAs/聚碳酸脂一维光子晶体的太赫兹波透射谱.研究结果发现,与一般由两种介电材料组成的一维光子晶体不同,由于掺杂半导体中自由载流子对太赫兹波存在较强的吸收,所以这种材料组成的一维光子晶体除可形成光子带隙外,还可以增强n-GaAs对太赫兹波的透射.同时还提出了一种基于这种一维光子晶体的太赫兹波调制器,通过外加电压控制半导体中电子浓度的大小可实现对太赫兹透射波幅度的调制.
关键词:
掺杂半导体光子晶体
太赫兹波
太赫兹波的调制 相似文献
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本文将石墨烯引入到常规光子晶体中构建一种新型光子晶体, 首次从理论上严格导出了决定其能带结构的色散关系, 由于色散关系中石墨烯电导率的存在导致了它具有与常规光子晶体有所不同的特殊光学性质, 我们发现, 随着费米能增大, 低频段能带迅速向高频移动, 而高频段能带移动缓慢, 导致了常规光子晶体没有的能带压缩现象的发生, 究其原因在于石墨烯在低频段电导率迅速变化, 而高频段电导率变化缓慢, 导致能带向高频压缩, 使得光波原先允许频率变成禁止传播, 而禁止频率变成允许传播. 相似文献
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Coupled resonator optical waveguides (CROWs) in complex two-dimensional (2D) photonic crystals (PCs) constructed with a portion of 12-fold photonic quasicrystals (PQs) are proposed. We show that enhanced transmission and slow light can be simultaneously achieved in such waveguides as well as general CROWs. Moreover, due to higher degree of flexibility and tunability of PQs for defect mode properties compared to conventional periodic PCs, multiple slow light bands can be flexibly obtained in CROWs constructed with complex 2D PCs. Our results may lead to the development of a variety of novel ultracompact devices for photonic integrated circuits. 相似文献