共查询到20条相似文献,搜索用时 31 毫秒
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讨论了一维负折射光子晶体对光脉冲传播的影响.通过对光脉冲的透射场强的数值计算发现,频谱处于一维负折射率材料光子晶体禁带中的短脉冲通过光子晶体后基本保持形状不变,而对同样的短脉冲通过传统的一维光子晶体的透射脉冲则出现严重畸变.当考虑负折射率材料的色散时,讨论了位相时间随光脉冲载波频率的变化情况. 相似文献
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一维光子晶体非线性色散特性的分析 总被引:10,自引:8,他引:2
从无限周期一维光子晶体的色散关系和有限周期光子晶体的透射系数两个方面,对有限和无限周期光子晶体有效折射率的实部和虚部特性曲线分别进行了计算和分析.结果表明一维光子晶体的色散曲线与弹性电偶极子的经典色散曲线类似,在光子晶体的导带为正常色散,而在禁带呈现反常色散.并且用简约布里渊和扩展布里渊区色散曲线对文献报道中存在的两种矛盾的计算结果进行了理论的探讨.解释了导致对一维光子晶体有效折射率计算存在两种不同结果的原因. 相似文献
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A type of photonic multiple quantum well (PMQWs) structure made of two different photonic crystals (PCs) with two kinds of single-negative materials is investigated. It is demonstrated by transfer matrix method that omnidirectional resonance modes are generated. The number of the resonance modes can be controlled by adjusting the periodic structure of the constituents. The resonance tunneling modes are weak dependence on incident angle and the scaling of the barrier photonic crystals. When the losses are taken into account, the effects of the losses coming from ENG media and MNG media on the resonance modes are striking difference. 相似文献
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Laxmi Shiveshwari 《Optik》2011,122(17):1523-1526
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. 相似文献
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采用平面波展开法和时域有限差分法,研究了光子晶体表面光波导的色散及光传输特性。研究结果表明,表面模的出现及其色散特性与表面介质柱的半径相关,色散曲线的斜率保持单调变化,并在最低或最高频率附近展现低群速度频率区。由于光子带隙和全内反射的共同影响,光场将沿晶体表面高效率地传输。研究结果为探索在光子晶体外部控制光传输具有重要的理论意义。 相似文献
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A low-loss and flat dispersion line-defect photonic crystal waveguide is proposed with a simplified waveguide-design on silicon-on-insulator (SOI) based on hexagonal lattice of 2D photonic crystals. A propagation loss of 3.6 dB/mm and flat dispersion over a large wavelength band is reported with an easy-to-implement design without disturbing the periodicity (keeping lattice constant and hole diameter fixed) in the line-defect photonic crystals. The combined effect of photonic crystals (in-plane periodicity) and the vertical layers on SOI results in efficient waveguiding and dispersion characteristics. 相似文献
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Exact analytical expressions for the dispersion relation of one-dimensional chiral photonic crystals
We consider one-dimensional photonic crystals made of alternating layers of two kinds of isotropic chiral media. The two layers are characterized by the dielectric permittivities ε1 and ε2, the magnetic permeabilities μ1 and μ2, the chirality parameters γ1 and γ2 and the thicknesses d1 and d2. By diagonalizing an 8 × 8 matrix derived from the two coupled wave equations satisfied by our system, we obtain exact analytical expressions for the dispersion relation for plane electromagnetic waves propagating at an arbitrary angle with respect to the layers. We present a detailed analysis of our dispersion relation and explore the evolution of the photonic band structure as the frequency, the chirality parameter and the incident angle vary, with a special emphasis on the generation of the cross- and co-polarization bandgaps. 相似文献
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We investigate the propagation of electromagnetic wave through photonic quantum-well structures constructed by one-dimensional photonic crystals with defect layers. It is shown that non-destroyed high transmittance of each separated resonant mode can be found if photonic quantum-well structures are properly connected. Experimental fabrication of combined photonic quantum-well structures is carried out, and the results agree with the numerical calculations very well. 相似文献
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The photonic band gaps in one-dimensional photonic crystals (PCs) are theoretically investigated. A new method to broaden the photonic band gaps is introduced. Based on the similar method, a kind of photonic crystals is constructed to generate photonic band gaps with proportioned central frequencies. This technology can be used for designing nonlinear PCs for harmonic generation. 相似文献
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《Physics letters. A》2019,383(21):2551-2560
Optical characteristics of two new graphene based photonic crystals are studied in detail. A structure containing alternating layers of graphene and SiO2 slabs is considered as the ideal crystal. The dependency of the photonic band gaps (PBGs) to the dielectric layer thickness and the period number is explored at first step. Potential of the proposed crystal to be used as an optical filter is then investigated. Adding a nonlinear electro-optic polymer as a defect layer, the alterations of the optical features are inspected. Results show that the defect layer insertion causes a resonant mode inside the PBGs. However, the location of the defect layer inside the crystal is very effective on both the frequency and width of the resonant mode. Tunability of the optical features is probed by taking into account of the dependencies to the wave incident angle, graphene chemical potential and the applied external voltage to the defect layer. 相似文献
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Laser-induced emission from rhodamine-B dye embedded in pseudo band gap opaline photonic crystals is discussed. The photonic crystals are fabricated using rhodamine-B doped polystyrene colloids and show 65% reflectance at the stop band centered at 604 nm. The reflectance of the crystal is increased to 74% by coating with a thin layer of gold. Both spontaneous and stimulated emissions of the dye are observed in the photonic stop band environment by exciting the crystal with the second harmonic (532 nm) of a Q-switched Nd:YAG laser. The thin layer of gold functioned as a high reflecting end mirror to the dye-doped cavity when the crystal is pumped from the substrate side. Angle-dependent suppression at the stop band wavelength is observed in the spontaneous emission of the dye. Spectrally narrow stimulated emission and lasing is achieved in the gold coated dyed PhC at a threshold pump power of 60 mW in a selective direction of 22° from the direction of excitation. By studying emission from several photonic crystals with different number of layers, it is concluded that a sharp threshold for lasing is not observed in uncoated photonic crystals when they contained fewer than 30 ordered layers and lesser than 70% reflectance. 相似文献
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组合一维光子晶体全能反射器 总被引:18,自引:11,他引:7
为了能充分地展宽一维光子晶体的全方位禁带,从一维光子晶体禁带结构的特点出发,对于不发生Brewster效应的一维光子晶体,提出了通过两个或两个以上一维光子晶体的组合来实现和展宽一维光子晶体全方位禁带的理论依据和最佳组合方式.并给出了所提出的组合方式下相关参数的定量计算公式. 最后用传输矩阵法进行了数值模拟计算,对提出的组合方式进行验证,计算结果与预期结论符合很好. 相似文献
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C. Jamois R. B. Wehrspohn L. C. Andreani C. Hermann O. Hess U. Gsele 《Photonics and Nanostructures》2003,1(1):1-13
A review of the properties of silicon-based two-dimensional (2D) photonic crystals is given, essentially infinite 2D photonic crystals made from macroporous silicon and photonic crystal slabs based on silicon-on-insulator basis. We discuss the bulk photonic crystal properties with particular attention to the light cone and its impact on the band structure. The application for wave guiding is discussed for both material systems, and compared to classical waveguides based on index-guiding. Losses of resonant waveguide modes above the light line are discussed in detail. 相似文献
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Based on the non-symmetric transmission-line method, the band gap structure of disordered chiral photonic crystals (CPC) has
been investigated. The influence of the chiral parameters, the disorder, the periods and the refractive index on the band
gap structure has been discussed. It is found that the photonic band gap (PBG) in CPC is more obvious than that in the conventional
photonic crystals, and the PBG can be increased by increasing the periods or the contrast of the refractive index of the two
media. It is also found that the existence of disorder will influence the band edge of the PBG, and such influence will increase
with the increment of periods or the contrast of the refractive index of the two media. 相似文献