基于法拉第效应磁化等离子体光子晶体FDTD分析

通过增加外磁场来调控等离子体光子晶体的光子带隙结构,采用时域有限差分算法分析了由本征层为磁化等离子体层和其他电介质材料层交替堆叠而成的磁化等离子体光子晶体的光子带隙结构,数值模拟中采用完全匹配层吸收边界条件以防止边界的反射。由于外磁场的法拉第磁光效应,使等离子体的介电常数随着外磁场的变化而改变。数值结果表明,等离子体光子晶体的带隙特性在一定的频率范围相应地得到调节,实现了频率低于等离子体频率的电磁波也能在等离子体中传播。     

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通过增加外磁场来调控等离子体光子晶体的光子带隙结构,采用时域有限差分算法分析了由本征层为磁化等离子体层和其他电介质材料层交替堆叠而成的磁化等离子体光子晶体的光子带隙结构,数值模拟中采用完全匹配层吸收边界条件以防止边界的反射。由于外磁场的法拉第磁光效应,使等离子体的介电常数随着外磁场的变化而改变。数值结果表明,等离子体光子晶体的带隙特性在一定的频率范围相应地得到调节,实现了频率低于等离子体频率的电磁波也能在等离子体中传播。     

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用时域有限差分法研究了电磁波在等离子体光子晶体中的传播特性。数值模拟中使用完全匹配层吸收边界条件,计算了电磁波通过等离子体光子晶体的反射和透射系数。讨论了等离子体密度、等离子体温度、介电常数比和引入缺陷层对等离子体光子晶体光子带隙的影响。     

Enlargement of the omnidirectional photonic band gap by one-dimensional plasma-dielectric photonic crystals with fractal structure

In this paper, an omnidirectional photonic band gap (OBG) which originates from Bragg gap compared to $\text{ zero- }\overline{n}$ zero- n ¯ gap or single negative (negative permittivity or negative permeability) gap, realized by one-dimensional plasma-dielectric photonic crystals with fractal structure (Thue–Mores aperiodic structure), which is composed of plasma and one kind of homogeneous, isotropic dielectric is theoretically studied by the transfer matrix method in detail. Such OBG is insensitive to the incident angle and the polarization of electromagnetic wave. From the numerical results, the bandwidth and central frequency of OBG can be notably enlarged by tuning the thickness of plasma and dielectric layers but cease to change with increasing the Thue–Mores order. The OBG also can be manipulated by the plasma density. Moreover, the plasma collision frequency has no effect on the bandwidth of OBG.     

基于横向磁光效应磁化等离子体光子晶体的光子带隙特性

通过外加与电磁波传播方向垂直的磁场来调控等离子体光子晶体的光子带隙结构。采用时域有限差分方法数值分析了由本征层为等离子体层和其他电介质材料层交替堆叠而成的磁化等离子体光子晶体的光子带隙结构和频谱特性。数值结果表明,光子晶体中等离子体的介电常数随着外磁场大小的变化而改变,从而使磁化等离子体光子晶体的带隙特性在一定的频率范围相应地得到调节。     

横磁模式下二维非磁化等离子体光子晶体的线缺陷特性研究

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     

PBG properties of three-component 2D photonic crystals

In this paper we analyze theoretically how the introduction of the third component into the two-dimensional photonic crystal influences the photonic band structure and the density-of-states of the system. We consider the periodic array of cylindrical air rods in a dielectric, and the third medium is introduced as a ring-shaped intermediate layer of thickness d and dielectric constant _i between the air pores and the dielectric background. Using the plane wave method, we have obtained the band structures for the 2D triangular lattice photonic crystals. The dependencies of TE and TM band gaps’ widths and gaps’ edges position on the interlayer dielectric constant and interlayer thickness were analyzed. In the framework of this approach, we have estimated the influence of the surface oxide layer on the band structure of macroporous silicon. We observed the shift of the gaps’ edges to the higher or lower frequencies, depending on the interlayer thickness and dielectric constant. We have shown that the existence of a native oxide surface layer should be taken into consideration to understand the optical properties of 2D photonic crystals, particularly in macroporous silicon structures.     

无规结构全角高反一维光子晶体的场强分布

因一维光子晶体的许多应用由其场强分布特性所决定，本文研究了无规全角高反一维光子晶体场强分布的性质，结果表明在带隙内,两者的场强分布无明显差别,但在研究各种应用和器件关系最密切的带隙边缘, 周期结构的场强分布只有对称性的一种；无规结构光子晶体的谱带边缘电场分布特性则完全可按应用要求进行设计和控制，为光子晶体器件设计提供了全新的思路. 关键词： 光子晶体 无规结构 光子能隙 全角高反 场强分布     

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在理想条件下,为了研究等离子体参数、填充率、入射角度和介质层相对介电常数对一维三元磁化等离子体光子晶体的禁带特性的影响,用由传输矩阵法计算得到的TE波任意角度入射时的左旋极化波(LCP)和右旋极化波(RCP)的透射系数来研究其禁带特性。结果表明,仅增加等离子体碰撞频率不能实现禁带宽度的拓展,改变等离子体频率、填充率和介质层的相对介电常数能实现对禁带宽度和数目的调谐。改变等离子体回旋频率能实现对右旋极化波的禁带的调谐,但对左旋极化波的禁带几乎无影响。入射角度的增大使得禁带低频区域带宽变大,而高频区域带宽则是将先减小再增大。     

Zero permittivity band characteristics in one-dimensional plasma dielectric photonic crystal

We consider the oblique propagation of electromagnetic waves in one-dimensional plasma dielectric photonic crystals, the superlattice structure consisting of alternating plasma and dielectric materials using transfer matrix method. Our results show that photonic band gaps for all polarizations can be obtained in one-dimensional plasma dielectric photonic crystals. These structures can exhibit a new type of band or gap, for the incidence angles other than normal incidence, near frequencies where the electric permittivity of the plasma layer changes sign. This new band or gap arises, from the dispersive properties of the plasma layer, only for TM polarized waves and its width increases with the increasing angle of incidence. This differential behaviour under polarization can be utilized in the design of an efficient polarization splitter. The band characteristic is affected by the plasma width, the plasma density, dielectric width, the dielectric constant of the dielectric medium and angle of incidence.     

Anomalous dispersion in one-dimensional plasma photonic crystals

The anomalous dispersion in one-dimensional plasma photonic crystals (1-DPPCs) is studied. The width of band pass and band gap are compressed, the phase velocity decreases and the cup-off frequency comes close to the frequency of plasma when EM wave oblique incidence on 1-DPPCs. The band gaps are affected by the thickness of plasma, the dielectric constant of the dielectric material, the plasma density and the angle of incidence. Superluminal negative group velocity is discovered in this study. This character is interesting for scientists and may have a potential application.     

一维磁化等离子体光子晶体非互易特性研究

在理想条件下,为了研究等离子体回旋频率、等离子体频率、等离子体层厚度、周期常数和入射角在TM模式下对一维磁化等离子体光子晶体的非互易特性的影响,用利用传输矩阵法计算得到的TM波正向和反向传播的透射率来研究其非互易特性。研究结果表明,增加等离子体回旋频率和入射角度能够改善非互易特性;而一味地增加等离子体频率和等离子体层厚度将会使得非互易传播特性变得恶化;增加周期常数不能明显地改善非互易传播特性,但是通过改变外加磁场的施加方式能够改善其非互易特性。     

等离子体光子晶体的FDTD分析

等离子体光子晶体是等离子体和介质（真空）构成的人工周期性结构.用分段线性电流密度 递归卷积时域有限差分（PLCDRC-FDTD）算法分析了等离子体光子晶体和缺陷等离子体光子 晶体.从时域的角度分析了高斯脉冲在等离子体光子晶体中的传播过程，给出了时域反射和 透射波形.然后，从频域的角度分析了等离子体光子晶体和带缺陷的等离子体光子晶体的电 磁反射系数和透射系数.计算表明，等离子体光子晶体对频率小于等离子体频率的低频电磁 波几乎完全反射，而透射的电磁波则为频率高于等离子体频率的电磁波.在高频，等离子体 光子晶体则出现类似一般光子晶体的光子带隙特性. 关键词： 等离子体 光子晶体 时域有限差分法 等离子体光子晶体     

Investigation of the properties of extraordinary mode in three-dimensional magnetized plasma photonic crystals with diamond lattices as Voigt effects are considered

In this paper, the properties of extraordinary mode for two types of three-dimensional magnetized plasma photonic crystals (3D MPPCs) composed of homogeneous dielectric and magnetized plasma with diamond lattices are theoretically investigated for electromagnetic (EM) wave based on a modified plane wave expansion (PWE) method, as Voigt effects are considered. As EM wave propagates in such 3D MPPCs, the EM wave can be divided in two modes due to the influence of Lorentz force. One is named extraordinary mode and another is ordinary mode. The equations for calculating the dispersive relationships for extraordinary mode as propagating through two types of structures (dielectric spheres immersed in magnetized plasma background or vice versa), are theoretically deduced. The influences of dielectric constant of dielectric, plasma collision frequency, filling factor, the external magnetic field and plasma frequency on the properties of extraordinary mode for both types of MPPCs are investigated in detail, respectively, and some corresponding physical explanations are also given. From the numerical results, it has been shown that not only the locations but also bandwidths and relative bandwidths of the photonic band gaps obtained by extraordinary mode for both types of 3D MPPCs can be manipulated by plasma frequency, filling factor, the external magnetic field and the relative dielectric constant of dielectric, respectively. However, the plasma collision frequency has no effect on the frequency ranges and relative bandwidths of PBGs for two types of 3D MPPCs. The locations of flatbands regions cannot be tuned by any parameters except for plasma frequency and the external magnetic field.     

磁化等离子体光子晶体缺陷态的研究

采用磁化等离子体的分段线性电流密度卷积时域有限差分(PLCDRC-FDTD)算法研究具有单一缺陷层的一维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率,并讨论该光子晶体的缺陷层厚度、位置、周期常数和等离子体参数对其缺陷模的影响. 结果表明,改变位置和周期常数不会影响缺陷模的频率,改变缺陷层的厚度可以增加缺陷模数,改变等离子体参数能同时影响缺陷模的频率和峰值. 关键词： 磁化等离子体光子晶体 光子晶体 缺陷模 时域有限差分法     

Numerical study on characteristic of two-dimensional metal/dielectric photonic crystals

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.     

TM模式下二维非磁化等离子体光子晶体的禁带调制特性分析

采用时域有限差分法(FDTD)中的分段线性电流密度卷积(PLCDRC)算法研究了TM波入射时二维非磁化等离子体光子晶体的禁带特性.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介质圆柱的介电常数、晶格常数、介质圆柱半径,周期常数和等离子体参数对其禁带特性的影响.结果表明,增加周期常数和等离子体碰撞频率不会改变禁带宽度,增加介质圆柱的相对介电常数和等离子体频率可以展宽禁带的宽度. 当填充率一定时,减小介质圆柱的半径和晶格常数可以实现禁带的拓展. 关键词： 等离子体 光子晶体 禁带 PLCDRC算法     

Design of an omnidirectional band gap independent of ambient media refractive indices by using a heterostructure magnetic photonic crystal

This paper aims to study the general conditions under which omnidirectional band gaps (OBGs) are achieved by using heterostructure magnetic photonic crystals (HMPCs). These structures contain periodic layers with alternative dielectric permittivity and magnetic permeability. The proposed design offers the stacking of two magnetic photonic crystals (MPCs), where one MPC has Brewster’s angle at TE polarization and another has the angle at TM polarization. The propagation of electromagnetic waves is investigated by means of the transfer matrix method. Also, the total reflection frequency range for any incident angle and polarization is discussed in this paper. As a conclusion, although each MPC has no OBG individually, the proposed HMPC may contain an OBG. The main advantage of the proposed design is that the obtained OBG is independent of the ambient media refractive index. Therefore, it can be used in engineering omnireflectors in integrated photonics.     

Magneto-optical Faraday effects in dispersive properties for three-dimensional magnetized plasma photonic crystals

The dispersive properties of three-dimensional magnetized plasma photonic crystals composed of homogeneous magnetized plasma spheres immersed in isotropic dielectric host with face-centered-cubic lattices are theoretically studied based on plane wave expansion method, as the magneto-optical Faraday effects of magnetized plasma are considered. The equations for calculating the band structures are theoretically deduced. The photonic band gap and a flatbands region can be obtained. The influences of host dielectric constant, plasma collision frequency, filling factor, external magnetic field and plasma frequency on the dispersive properties are investigated in detail, respectively, and some corresponding physical explanations are also given. The numerical results show that the photonic band gap can be manipulated by the plasma frequency, filling factor, external magnetic field and host dielectric constant, respectively. However, the plasma collision frequency has no effects on photonic band gap. The location of flatbands region cannot be tuned by any parameters except for the plasma frequency and external magnetic field.     

一维等离子体光子晶体的带隙研究

采用时域有限差分方法(FDTD),结合等离子体计算中的分段线性电流密度卷积技术(PLJERC)对一维等离子体光子晶体(1D-PPC)进行了数值模拟,给出了微分高斯脉冲在一维等离子体光子晶体中的传播过程。计算得到的带隙结构与K-P模型方法的结果一致。计算并分析了等离子体频率、介质介电常数、等离子体-介质层的厚度比以及周期厚度对一维等离子体光子晶体带隙结构的影响。