含负折射率材料1维光子晶体的偏振无关非全向的缺陷模

运用光学传输矩阵理论,研究了含负折射率材料1维光子晶体缺陷模的偏振特性。结果显示,零均折射率带隙中缺陷模对入射角和偏振有较强的依赖。通过对缺陷层参数的优化设计,得到了一系列的偏振无关非全向缺陷模,这是传统1维光子晶体中不能出现的。应用这些缺陷模,设计了低通、高通、带通空间滤波器。与传统光子晶体空间滤波器相比,这些空间滤波器具有偏振无关的优点。     

含负折射率材料的一维光子晶体缺陷模式的研究

采用光学传输矩阵方法,研究了由正折射率材料和负折射率材料交替组成的一维光子晶体中带有缺陷层时的光学传输特性.计算了含有普通电介质插层和有吸收的介质插层两种情况下的透射谱.结果表明,在正入射时,对于普通电介质插层,随插层厚度的增大,缺陷模的个数增多;对于有吸收特性的介质插层,随插层厚度的增大和吸收特性的增强,缺陷模式并没有出现,而是表现为对透射峰的明显增益.     

含负折射率缺陷的一维光子晶体的杂质带

利用传输矩阵方法研究了含负折射率缺陷的一维光子晶体的透射谱.以19个周期的1/4波堆存在3个负折射率缺陷的光子晶体为例进行了数值计算.结果表明:如果改变缺陷的折射率,缺陷模之间的耦合作用将发生改变,带隙中形成的杂质带也随之改变; 当这个折射率取适当值时,在禁带中出现多个尖锐的透射峰,与正折射率缺陷构成的杂质带不同.     

含负折射率材料一维光子晶体的全方位带隙和缺陷模

运用光学传输矩阵理论,研究了含负折射率材料一维二元光子晶体的禁带特性和局域模特性,发现了一种新型全方位光子带隙.与传统的Bragg带隙相比,这种新型全方位光子带隙的中心频率和带宽对入射角的变化不敏感.讨论了引入缺陷层后,入射角变化和各层介质厚度做一定比例的缩放时对缺陷模位置的影响.这种特性在具有固定带宽的全方位反射器和微波技术中全方位或大入射角滤波器方面有重要的应用价值.     

含负折射率材料的一维光子晶体的光学传输特性

采用光学传输矩阵方法,模拟研究了由正折射率材料和负折射率材料交替组成的一维光子晶体的光学传输特性.计算了这种含负折射率材料的一维光子晶体的透射谱和色散关系.结果表明,在正入射时,含负折射率材料的光子晶体的带隙要比传统的光子晶体要大得多,并具有狭窄的透射带,从光学薄膜理论的色散关系出发解释了形成上述现象的原因.讨论了在不同的偏振模式下,光以中心波长入射时,反射率随着入射角度的变化关系.发现含负折射率材料的一维光子晶体具有更好的角度特性,可以用来实现对中心波长的全方位反射.     

利用含负折射率材料的光子晶体实现角度滤波器

利用光子晶体的共振隧穿效应，并结合由负折射材料引起的零平均折射率带隙，设计出一种新型的角度滤波器，使得对于某一频率范围内的入射电磁波仅在特定入射角度的波能够全透，而其他角度的波不能透过.这将在微波器件乃至光学器件上有广泛应用. 关键词： 光子晶体 负折射率材料 共振隧穿     

含负折射率缺陷的一维光子晶体的杂质带

利用传输矩阵方法研究了含负折射率缺陷的一维光子晶体的透射谱.以19个周期的1/4波堆存在3个负折射率缺陷的光子晶体为例进行了数值计算.结果表明:如果改变缺陷的折射率,缺陷模之间的耦合作用将发生改变,带隙中形成的杂质带也随之改变; 当这个折射率取适当值时,在禁带中出现多个尖锐的透射峰,与正折射率缺陷构成的杂质带不同.     

含负折射率材料的异质结构光子晶体的光学传输特性

利用传输矩阵法研究了正负折射率材料构成的异质结构光子晶体的光学传输特性。结果表明:当入射波正入射时,在这种异质结构光子晶体内出现了光子带隙,并且带隙内出现了3个极窄的透射峰,这是正负交替光子晶体和常规材料构成的同周期一维异质结构光子晶体所不具有的新颖物理特性。计算了这种异质结构光子晶体的透射谱。发现:这3个透射峰不敏感于入射角的变化,而在带隙两侧的透射峰则会随着入射角增大统一向带隙靠近;能带敏感于晶格厚度和周期数的变化。     

含负折射率材料的一维“啁啾”光子晶体的透射谱

将"啁啾"函数引入到含负折射率材料的一维光子晶体中,利用转移矩阵法对这种光子晶体的透射谱进行了研究。通过计算模拟了这种光子晶体的透射谱随入射角、频率的变化关系,并计算了这种晶体的复有效折射率的表达式。结果表明,当"啁啾"函数对厚度调制不大时,该晶体具有很宽的反射带,并且反射带对入射角度反应不敏感,其原因是由于其复有效折射率的实部几乎为0,而虚部较大。利用这一特性可以用来制作高品质的宽带全方位反射镜。     

含负折射率材料的一维光子晶体禁带特性

运用光学传输矩阵和色散关系理论,研究了由正折射率材料和负折射率材料交替组成的一维光子晶体的禁带特性,发现了一种新型带隙—零平均折射率带隙。与传统的Bragg带隙相比,只要两种介质厚度的比例保持不变,这种零平均折射率带隙的边缘频率,与光子晶体的晶格常数无关,并利用一个等效的传输线模型得出了带隙边缘频率的数学表达式,解释了这个性质。     

Periodic defect modes of one-dimensional crystals containing single-negative materials

The transmission properties of a one-dimensional (1D) photonic crystal containing two kinds of single-negative (permittivity or permeability negative) material with an inserted array of defects (RHM and LHM) were presented by the transfer matrix method (TMM). The dependence of the defect modes on the structure parameters was discussed by using the TMM. In contrast to the Bragg gaps, the properties (the central frequency and width of the gap) of zero effective phase (zero−φ_eff) and gap are invariant with a change in scale length and insensitive to the incident angles. The property of the periodic defect modes in the SNG host periodic structure was studied. It illustrates that the defect modes properties changed more by insert periodic defect than by single-media defect. The defect modes are sensitive to the parameters of the defect layers and the incident angle.     

Characterization for defect modes of one-dimensional photonic crystals containing metamaterials

Transmission studies for one-dimensional photonic crystals(1DPCs)containing single-negative(SNG)materials inserted with multiple defects are presented.The numbers and positions of the defect modes inside zero-phase(zero-φeff)gap are found to be well characterized by effective medium theory.     

Properties of defect modes in one-dimensional symmetric defective photonic crystals

We theoretically investigate the properties of defect modes in one-dimensional symmetric defective photonic crystals. We consider three defective photonic crystal structures, air/[(AB)^NsA^α(BA)^Ns]^Np/air, air/[(AB)^NsAB^βA(BA)^Ns]^Np/air, and air/{[(AB)^NsAB^βA(BA)^Ns]B^γ}^Np−1[(AB)^NsAB^βA(BA)^Ns]/air, where A and B are respectively taken to be the high- and low-index dielectric materials. The first has a defect layer of A^α, the second has a composite defect, AB^βA, and the third has a interleaving defect B^γ. The effect of thickness on the defect mode is studied by varying the parameters α, β, and γ, respectively, for the above model structures. It is found that the positions and the number of defect modes can be significantly changed due to the change in the defect thickness. In addition, by increasing the repeated number N_p, we can have multiple defect modes, leading to a possible design of tunable multichannel filter.     

Analytical investigation of one-dimensional photonic crystals with a dielectric-superconducting pair defect

We have studied the dielectric-superconducting pair defect embedded into one-dimensional photonic crystals by an analytical method based on the Kronig-Penny model. The superconducting defect has been considered by using of two-fluid model whose permittivity depends on the frequency and superconductor parameters. We have showed that in contrast to the usual defect modes, superconducting defect modes are nearly invariant upon the change of defect size and with increasing defect sizes, the enhancement behavior is observed in the peak of electric field profiles. In addition, the physical parameters have less effect on the defect modes, which is placed under cutoff frequency of superconductor.     

Aberration-free two-thin-lens systems based on negative-index materials

Since the complete correction of all five monochromatic Seidel aberrations for a singlet lens with random shape or a two-thin-lens system is unprocurable merely by using the conventional positive-index materials both in theory and practice, this paper proposes that when one or both of the two lenses is/are made from negative-index materials, an imaging system composed of a pair of spherical thin lenses is possible to form a real image, in air, free from all five monochromatic Seidel aberrations. The calculated numerical solutions to the structural parameters of such lens systems possessing superior performance are provided and examples of them are illustrated for the given combinations of the two lenses＇ refractive indices, including an ultimately-remote imaging system.     

一维多缺陷光子晶体的缺陷模

设计了一个多缺陷的一维光子晶体,并利用传输理论研究其透射谱.利用泰勒展式的一级近似,得到了缺陷模频率的解析表达式,进而得到紧束缚理论中的耦合因子.这些结论与实验结果或数值模拟相符合,可以很好地描述缺陷模的有关规律,对多通道滤波器的设计具有指导意义. 关键词： 光子晶体 缺陷模 紧束缚方法 耦合因子     

Optical properties of chiral photonic crystals with an anisotropic defect layer

Properties of defect modes in chiral photonic crystals with an anisotropic defect are considered. The influence of the defect layer thickness, its location in the crystal and orientation of its optical axis, as well as of the chiral photonic crystal thickness on the properties of defect modes is studied. It is shown that at certain values of the defect layer thickness the medium loses its main property, namely, the polarization dependence of the diffraction reflection. At certain thicknesses of the defect layer this system transforms from the source of the right circular polarization into the source of the left circular polarization, if the layer position in the chiral photonic crystal changes.     

Wave propagation inside one-dimensional photonic crystals with single-negative materials

The propagation of light waves in one-dimensional photonic crystals (1DPCs) composed of alternating layers of two kinds of single-negative materials is investigated theoretically. The phase velocity is negative when the frequency of the light wave is smaller than the certain critical frequency ω_cr, while the Poynting vector is always positive. At normal incidence, such 1DPCs may act as equivalent left-handed materials. At the inclined incidence, the effective wave vectors inside such 1DPCs do refract negatively, while the effective energy flows do not refract negatively. Therefore, at the inclined incidence, the 1DPCs are not equivalent to the left-handed materials.     

Phase response of omnidirectional reflection one-dimensional photonic crystals and defect modes

In this paper, we investigate the phase properties of light reflected from one-dimensional omnidirectional reflection photonic crystal. We observe that the phase changes drastically at large incident angles. This asymmetrical phase change should be considered at oblique incidence, and various phase compensators and retarders can be designed by this nonlinear curved surface of phase shift. Furthermore, for the coupled defect 1D PC, the phase change depends mainly on the top of the sharp peak of the weak undulation within the rectangular defect band, because the top of the peak of the undulation is very sharp, i.e. large phase change look like within almost a single frequency. This drastic phase change can be used to design phase controllers.