共查询到19条相似文献,搜索用时 109 毫秒
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研究了慢光模式在SOI(silicon-on-insulator)材料光子晶体线缺陷弯折波导中的传输特性. 通过优化波导弯折处的结构参数,慢光模式在光子晶体60°与120°弯折波导中的透射率提高10倍以上,归一化透射率分别达到80%和60%以上. 为了进一步减慢光速,设计了新颖的高Q值耦合腔弯折波导结构,在归一化透射率达到75%的基础上,光波群速度低至c/170(c为真空光速). 研究结果对于增强光子晶体的慢光效应,提高光子晶体慢光器件的微型化和集成化都有一定的积
关键词:
光子晶体
慢光
弯折波导
透射率 相似文献
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将二维三角晶格光子晶体波导和微腔结构结合,优化设计了一种二维三角晶格光子晶体共振耦合腔波导,运用时域有限差分法(FDTD)模拟共振耦合腔波导TE偏振光的透射谱,通过透射谱得到传输光的透射率和群速度。结果表明,合适参数的二维三角晶格共振耦合腔波导在波长1.551μm处的群速度为c/130、透射率为20.1%,在波长1.502μm处的群速度为c/50、透射率为29.2%。运用平面波展开法(PWE)计算的该波导的能带结构对慢光特性进行了分析。这种慢光特性的光子晶体波导将在光存储、光延迟及光子集成等方面有潜在的应用价值。 相似文献
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采用时域有限差分法中的分段线性电流密度卷积算法,研究具有单一缺陷层的一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率,并讨论该光子晶体的缺陷层介电常数、厚度、位置、光子晶体的周期常数和等离子体参数对其缺陷模的影响.结果表明,改变以上参数可获得不同的缺陷模.
关键词:
时域有限差分法
非磁化等离子体光子晶体
缺陷模 相似文献
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《光学学报》2010,(7)
研究了二维光子晶体耦合腔波导的结构对慢光特性的影响,发现微腔间的距离n、填充因子r/a和缺陷柱的尺寸rd是影响光子晶体禁带中慢光导模传输特性的重要参数。随着缺陷微腔间距离的增加,导模群速度vg急剧减小;当填充因子和缺陷柱尺寸增加时,导模向低频方向移动,同时,导模群速度降低;填充因子和缺陷柱尺寸降到一定数值后,vg达到最小值,此后,当r和rd分别超出其特定值继续增大,导模群速度反而增大。取微腔之间介质柱个数为6,普通介质柱尺寸为r=0.22a,a为光子晶体晶格常数,缺陷柱尺寸为rd=0.12a,得到导模群速度最大值vgmax1.93×10-3c,带边处vg10-4c(c为光速)。这一结果显示,通过基本结构设计可以实现对光子晶体耦合腔光波导中慢光的有效控制,这将为基于光子晶体功能器件的设计和应用提供有效的支持。 相似文献
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设计了一种双芯高双折射光子晶体光纤,采用多极法(multipole method)和光纤的模式耦合理论研究了光纤的双折射、耦合长度以及色散特性.数值研究发现,对于空气孔节距 Λ=1.2 μm,空气孔直径d=1.0 μm的光纤,在1.55 μm处双折射度为1.24×10-2;对应x偏振模的耦合长度为21.6 μm,对应y偏振模的耦合长度为24.3 μm. 这种具有高保偏度和极短耦合长度的双芯光子晶体光纤对于微型光子器件的研制具有重
关键词:
光子晶体光纤
双芯
双折射
耦合长度 相似文献
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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 相似文献
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利用光波在一维各向异性圆柱掺杂光子晶体中径向受限的条件,研究了光波在其中出现的模式量子效应,并利用特征矩阵法计算了TE波和TM波各模式的缺陷模的变化规律,得出了一些一维各向异性圆柱光子晶体缺陷模的新结构.缺陷模的频率和透射角都随模式量子数的增加而增大.同一模式缺陷模的频率随圆柱半径的增加而减小.
关键词:
圆柱光子晶体
各向异性介质
量子效应
缺陷模 相似文献
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We propose and analyze a novel photonic crystal pulse position modulator utilizing a coupled cavity waveguide delay line. Also, a nonlinear photonic crystal directional coupler is used as an all-optical switch in the proposed structure. The input data acts as the control signal of the switch and activates the switching operation. We show that the device size can be reduced significantly by designing the delay line to achieve a reduced group velocity and a quasi-flat impurity band. The size of the designed modulator is 32a × 16a, where a represents the lattice constant of the photonic crystal. The characteristics of the device are investigated by finite-difference time-domain (FDTD) and plane wave expansion (PWE) methods. 相似文献
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We analyze photonic scattering on a trimer with PT symmetry, where the photon propagates in an array of cavities. In the system, a passive and an active cavity couple to another cavity without loss and gain simultaneously, which is in the middle of the cavity array. Such three cavities can be regarded as the scattering target coupling to the unlimited number of cavities from two directions respectively. Our approach is to use the Schrödinger equation to calculate the reflection coefficient and transmission coefficient, and then let photonic transmission spreads from gain or loss cavity. It shows that the scattering of the photon is closely associated with the PT symmetric characteristic of the dynamics of the system. The atom’s modulation on the photonic transmission is also investigated. We found that the scattering center can behave as a photonic switch, which could be used potentially to control the photonic transmission. 相似文献
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A two-dimensional photonic crystal coupled-cavity waveguide is designed and optimized, the transmission spectrum is calculated by using the finite-difference time-domain method, and the group velocity of c/1856 is obtained. To our knowledge, this value of group velocity is the lowest group velocity in a photonic crystal waveguide calculated from its transmission spectrum so far. The result is confirmed by the photonic band structure calculated by using the plane wave expansion method, and it is found that the photonic crystal waveguide modes in a photonic band structure are in accordance with those in the transmission spectrum by using the finite-difference time-domain method. The mechanism of slow light in the coupled-cavity waveguide of photonic crystal is analysed. 相似文献
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利用微腔之间的立体耦合,提出了基于无源材料硅的双层光子晶体薄板H1(DLPCS-H1)腔,薄板之间为空气层.使用三维时域有限差分方法和Padé近似方法分析了DLPCS-H1腔的偶极模的场分布和品质因子.通过对中间空气层高度的优化使DLPCS-H1腔的偶极模的品质因子得到了显著的提高,大约为单层光子晶体薄板H1腔的偶极模的品质因子的4倍.此外,还研究了三层光子晶体薄板H1腔,它的偶极模的品质因子约为单层光子晶体薄板H1腔的偶极模的品质因子的7倍. 相似文献
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Diatoms as living photonic crystals 总被引:1,自引:0,他引:1
T. Fuhrmann S. Landwehr M. El Rharbi-Kucki M. Sumper 《Applied physics. B, Lasers and optics》2004,78(3-4):257-260
We present an analysis of the optical structure of a representative diatom, Coscinodiscus granii. The silica cell wall can be regarded as a photonic crystal slab waveguide with moderate refractive-index contrast. In a cell, at least two different patterns are found: a hexagonal array of pores with a large lattice constant in the valve, and a square array of holes with a small lattice constant in the girdle. It is demonstrated that light can be coupled into the waveguide and that there are some photonic resonances in the visible spectral range, which have been determined by band-structure calculations. PACS 42.70.Qs; 87.17.-d 相似文献
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Propagation of light through localized coupled-cavity modes in one-dimensional photonic band-gap structures 总被引:2,自引:0,他引:2
M. Bayindir S. Tanriseven E. Ozbay 《Applied Physics A: Materials Science & Processing》2001,72(1):117-119
We report on the observation of a new type of propagation mechanism through evanescent coupled optical cavity modes in one-dimensional
photonic crystals. The crystal is fabricated from alternating silicon-oxide/silicon-nitride pairs with silicon-oxide cavity
layers. We achieved nearly full transmission throughout the guiding band of the periodic coupled cavities within the photonic
band gap. The tight-binding (TB) parameter κ is determined from experimental results, and the dispersion relation, group velocity
and photon lifetime corresponding to the coupled-cavity structures are analyzed within the TB approximation. The measurements
are in good agreement with transfer-matrix-method simulations and predictions of the TB photon picture.
Received: 21 August 2000 / Revised version: 22 August 2000 / Published online: 9 November 2000 相似文献
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Zheng Han Delphine Néel Sylvain David Moustafa El Kurdi Philippe Boucaud 《Optics Communications》2010,283(21):4387-464
We propose an optimized design for the measurement in transmission of photonic crystal width-modulated line-defect cavities. By controlling the number of holes and rows that separate the cavity from the coupling waveguides, the measured quality factor of the cavity can be tuned to be close to the unloaded one. In the case of a weakly coupled cavity, we measure an ultra-high quality factor that reaches a value of 2 × 106. This value is not obtained for the largest spacing but for an intermediate one. This counter-intuitive result is supported by 3D-FDTD modeling. 相似文献
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一维光子晶体中多缺陷耦合导致的杂质带 总被引:17,自引:8,他引:9
利用传输矩阵方法研究了包含多个周期性分布的缺陷的一维光子晶体的透射谱.以33个周期的1/4波堆存在5个缺陷的光子晶体为例作了数值计算.结果表明,在周期性光子晶体中加入多个缺陷时,将在截止带中产生多个缺陷模.这些缺陷模构成的杂质能带依赖于缺陷在晶体中的分布.当缺陷密集时,缺陷模耦合较强,杂质带中透射峰相距较远,它们对应禁带中许多分立定域的杂质能级;当缺陷稀疏时,缺陷模耦合较弱,透射峰相距较近,分立的杂质能级趋于简并,由此形成一个很窄的通带. 相似文献