二维排列共振吸收介质的光学特性研究

从理论上提出了一种二维排列的共振吸收介质阵列，计算了介质阵列的透射、反射与吸收光谱，发现存在着类似一维主动光子晶体中的共振光子带隙，并且这种结构的布里渊区边界点与二维阵列中原子之间的频率共振是产生这种共振带隙的必要条件. 本文还进一步分析了光子带隙与结构参数、二维阵列中原子共振中心以及吸收线宽之间的依赖关系. 关键词： 二维共振吸收介质阵列 布里渊区 光子晶体     

Diffractionless flow of light in all-optical microchips

We introduce the concept of a hybrid 2D-3D photonic band gap (PBG) heterostructure which enables both complete control of spontaneous emission of light from atoms and planar light-wave propagation in engineered wavelength-scale microcircuits. Using three-dimensional (3D) light localization, this heterostructure enables flow of light without diffraction through micron-scale air waveguide networks. Achieved by intercalating two-dimensional photonic crystal layers containing engineered defects into a 3D PBG material, this provides a general and versatile solution to the problem of "leaky modes" and diffractive losses in integrated optics.     

空气环型二维光子晶体完全带隙特性研究

采用平面波展开法, 系统研究了空气环型二维光子晶体的完全光子带隙随结构参数变化而改变的规律, 并将其与普通的空气孔型和介质柱型二维光子晶体的完全带隙进行了比较. 研究表明: 空气环型二维光子晶体不仅可以获得更宽的完全带隙, 而且, 当介质折射率较低时, 其可以获得普通空气孔型和介质柱型二维光子晶体在低折射率条件下所无法获得的完全带隙. 关键词： 空气环型二维光子晶体 完全带隙 平面波展开法     

Controllable Photonic Band Gap and Defect Mode in a 1D CO2-Laser Optical Lattice

We propose a new method to form a novel controfiable photonic crystal with cold atoms and study the photonic band gap （PBG） of an infinite 1D CO2-laser optical lattice of SSRb atoms under the condition of quantum coherence. A significant gap generated near the resonant frequency of the atom is founded and its dependence on physical parameters is also discussed. Using the eigenquation of defect mode, we calculate the defect mode when a defect is introduced into such a lattice. Our study shows that the proposed new method can be used to optically probe optical lattice in situ and to design some novel and controllable photonic crystals.     

Photonic amorphous diamond structure with a 3D photonic band gap

We report that a full three-dimensional (3D) photonic band gap (PBG) is formed in a photonic amorphous structure in spite of complete lack of lattice periodicity. It is numerically shown that the structure "photonic amorphous diamond" possesses a sizable 3D PBG (18% of the center frequency for Si-air dielectric contrast) and that it can confine light at a defect as strongly as conventional photonic crystals can. These findings present important new insight into the origin of 3D PBG formation and open new possibilities in developing 3D PBG materials.     

光子晶体压力传感器的基本原理

通过研究一维光子晶体受压力后其光带隙性能的变化，提出了光子晶体压力传感器的原理.计算表明，压力的大小与禁带起始波长、截止波长和禁带宽之间呈简单的线性对应关系.这就提供了通过测量光带隙性能而感知外载荷或者通过施加载荷而调制光带隙性能的可能.由于光子晶体的结构周期和光波波长为一个数量级，也就有可能制造出一系列精巧的压力、温度传感器或者其他精密仪器. 关键词： 压力传感器 光子晶体 光带隙性能     

Band gaps of two-dimensional photonic crystal structure using conjugated polymer (3-octylthiophenes)

The possibility of using conjugated polymer (3-octylthiophenes, P3OT) as two-dimensional (2D) photonic band gap crystals was investigated. The different aspects were examined of the absolute photonic band gap (PBG) formation for 2D photonic crystals (PCs) consisting of P3OT pillars in air. The formation of PBG was exhibited and confirmed by a calculation of transfer matrix method (TMM). It was found that P3OT triangular structure could be good candidate for absolute inhibition of reflection in ultraviolet frequency region for given orientation.     

大带隙二维三角格子光子晶体结构参数的优化设计

光子晶体结构设计优化是理论研究的一个重要内容.运用平面波展开法对圆柱、方柱及正六边柱构造的二维三角格子光子晶体的禁带进行仿真计算,讨论了介质材料分别为GaAs、Si和Ge情况下,柱子形状、旋转角度、填充比的变化对完全光子禁带的影响.发现:对于二维三角格子光子晶体,相对于介质柱,空气柱更易获得完全光子禁带;而相对于圆柱及...     

基于太极形介质柱六角光子晶体禁带特性研究

提出了一种新型的非对称性散射体的二维六角晶格光子晶体结构–-太极形介质柱光子晶体. 利用平面波展开法从理论研究这种光子晶体结构的能带特性以及结构参数对完全禁带的影响. 研究表明:散射体对称性的打破, TE模和TM模能带宽度和数目都会有所增加, 有益于获得更宽的完全禁带以及更多条完全禁带.通过参数优化, 发现在ε = 17, R=0.38 μm, r=0.36R, θ = 0° 时, 获得最大完全带隙宽度0.0541(ωa/2πc); 在ε = 16, R=0.44, r=0.2R, θ = 0°时, 光子晶体完全带隙数目最多达到8条. 关键词： 光子晶体 禁带 平面波展开     

On transmittance and localization of the electromagnetic wave in two-dimensional graphene-based photonic crystals

Two-dimensional graphene-based photonic crystal (GPC) formed by a periodic array of the homogeneous dielectric cylinders etched in the alternating graphene and dielectric layers and its inverse counterpart are considered. The transmittance of the photonic crystal is obtained. The waveguide due to the localization of the electromagnetic wave on the lattice defect that breaks the translational symmetry of the GPC of two different topologies is studied. The different topologies of GPC are characterized by different photonic band structures with different widths of photonic band gaps (PBG) and provide different frequencies for the localized electromagnetic wave due to the defect. The frequencies of the localized mode for both type of the GPC, located inside the lowest PBG, are in the range of THz or tens of THz depending on the topology of the GPC. It is shown that the photonic band gap always can be tuned by changing the chemical potential of graphene to provide formation of the localized photonic mode due to the defect. The technological advantages of the GPC, as well as the opportunity to tune the PBG and the frequency of the localized electromagnetic wave in the terahertz region of spectrum for the GPC are discussed.     

Ag-SiO2多层薄膜对光子带隙的影响

采用超高真空电子束蒸发制备了一维紫外、可见光波段光子晶体.研究了在石英衬底上不同周期Ag/SiO2体系对光子带隙的影响.带隙位置与理论计算结果符合.发现二氧化硅层的厚度对带隙位置和银层的透过率有较大影响,厚度的增加降低了反射率,从而使光子带隙更加明显,当厚度达到12层时观察到清晰的光子带隙.     

Magnetic surface plasmon-induced tunable photonic bandgaps in two-dimensional magnetic photonic crystals

We experimentally studied magnetically controllable photonic band gaps (PBGs) in two-dimensional magnetic photonic crystals consisting of ferrite rods. Besides the conventional PBG that relates to Bragg scattering, two other types of PBG, resulting from magnetic surface plasmon (MSP) resonance and spin-wave resonance, respectively, are observed. The PBG due to MSP resonance is particularly interesting because of its analogy to surface plasmon in metal; furthermore, it is shown to be completely tunable by an external static magnetic field from both an experimental and a theoretical point of view.     

二维光子晶体线缺陷结构的光谱辐射特性

光子晶体的禁带特性是该新兴材料的最根本特征。本文运用平面波展开法(PWE)计算了一种正方晶格Si光子晶体材料的禁带特性,并基于该材料设计出一种红外波段的线缺陷光子晶体波导结构。运用时域有限差分法(FDTD)研究了线缺陷二维光子晶体波导宽度对通频带、电场强度及透射能量的影响,研究结果为二维光子晶体波导器件的开发和利用提供了理论支撑。     

大带隙二维光子晶体结构的研究

针对三种常见的介质柱横截面分别为正六边形,正方形和圆形的二维光子晶体,提出了一种增大光子带隙的方法.直角坐标系下,使X方向长度增大p倍,并以原点为中心旋转角度φ,通过调整p和φ来降低结构对称性,使用平面波展开法,对其进行了大量的仿真分析.结果表明,结构改变后的光子晶体具有较大的带隙率.对于三种介质柱的三角晶格结构的光子晶体,最大带隙率能达到12％以上,尤其对于正方柱三角晶格光子晶体,最大带隙率达到15.1％.     

FCC结构胶体光子晶体的制备及其带隙特性测量

基于对光纤传输特性和胶体光子晶体制备方法的研究,提出了用外加电场控制的方法制备光子带隙位于通讯波段的FCC结构的胶体光子晶体,并用光纤系统测试胶体光子晶体的带隙特性.采用RSOFT模拟了胶体光子晶体的带隙,分析了带隙位于通讯波段时所需的胶体微球的基本参量(微球折射率和直径).采用自组装的方法,用步进电机控制玻璃基片向上的拉升速率.速率为5 μm/s,同时外加一电场.用扫描电镜观测胶体晶体的表面形貌,并设计了单模光纤系统测量胶体光子晶体的带隙特性.测试的透射谱线表明胶体光子晶体的带隙中心波长为1552 nm.测试结果和模拟结果具有很好的一致性,误差只有2 nm.     

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。     

Investigation of photonic band gap in a one-dimensional lossy DNG/DPS photonic crystal

The effects of losses on the photonic band gap (PBG) in a one-dimensional lossy double-negative (DNG)/double-positive (DPS) photonic crystal are theoretically investigated. Using the Lorentz expressions for the permittivity and permeability for the dispersive and lossy DNG material, it is found that the magnetic loss, in comparison with the electric loss, has a more salient influence on the PBG. The magnetic loss is shown to play a vitally important role in the analysis of PBG for this DNG/DPS photonic crystal.     

Photonic bandgap plasmonic waveguides

A type of a plasmonic waveguide has been proposed featuring an "open" design that is easy to manufacture, simple to excite and offers convenient access to a plasmonic mode. Optical properties of photonic bandgap (PBG) plasmonic waveguides are investigated experimentally by leakage radiation microscopy and numerically using the finite element method confirming photonic bandgap guidance in a broad spectral range. Propagation and localization characteristics of a PBG plasmonic waveguide have been discussed as a function of the wavelength of operation, waveguide core size, and the number of ridges in the periodic reflector for fundamental and higher order plasmonic modes of the waveguide.     

Analysis of Antennas with PBG Substrate

The use of photonic materials has been used in the theory of optical waves. The PBG (Photonic Band Gap) theory and material, was developed recently for optical frequencies and can be easily applied to millimeter waves, microwaves and planar antenna frequencies. The presence of photonic materials as substrate in antennas has some good characteristics such as, supression of light spontaneous emission and suppression of surface waves, allowing the application in planar antenna array. In this work an elaborate analysis using the full wave Transverse Transmission Line - TTL method, that provides efficient and concise results is applied to the planar antennas array with PBG substrate.     

Study on maximum band gap of two-dimensional photonic crystal with elliptical holes

In this paper, the maximum photonic band gap (PBG) of two-dimensional (2D) photonic crystal (PC) with elliptical air holes was studied by the finite-difference time-domain (FDTD) method based on changing the ratio (semi-major axis length of elliptical hole to the filling ratio) and azimuth angle of elliptical holes, respectively. It is shown that the PBG exhibits a peak value when the ratio of semi-major axis length to the filling ratio is equal to 0.86 approximately by increasing the filling ratio, and central frequency and the low boundary frequency of PBG decrease linearly with the increasing of semi-major axis length. In the aspect of the influence of azimuth angle from 0 to 90°, the PBG presents a minimum value, and central frequency and the low boundary frequency of PBG become high non-linearly by the increasing of azimuth angle to any filling ratio.