共查询到20条相似文献,搜索用时 62 毫秒
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为了得到二氧化钛反蛋白石光子晶体中影响光子定域化的规律,基于Mie散射理论和低浓度近似,对光子定域化参量进行了数值计算与理论分析,发现在该氧化物的剩余射线区内,入射波长和散射体大小对光子定域化有明显的影响.结果表明,在散射体浓度为10%,相对折射率大于3.8时,在中红外区13.3~15.3 μm范围内出现了光子定域化现象,并随着散射体半径的增大,定域化区向长波方向移动;同时,定域化参量先增大后减小.研究结果为实验上在该类光子晶体中实现光子定域化现象提供了理论参考. 相似文献
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提出一些折射率比锗还高的中红外材料(第一类)以及中红外反常色散材料(第二类)可以用于无序介质的光子定域化研究.基于Mie散射理论的研究发现,即使在低浓度散射体近似下,也容易在第一类无序介质中实现光子定域化;同时可在第二类无序介质中实现一定意义下(含一定的吸收)的光子定域化,且频率位于各自的剩余射线带内.研究还发现,基质的折射率效应在这两类无序介质中的作用完全不同.还提出了散射体平均等效散射截面饱和的假设,讨论了因此而导致的问题
关键词:
光子定域化
无序介质
中红外
反常色散 相似文献
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基于Mie散射理论的光子晶体安德森定域化研究 总被引:1,自引:0,他引:1
基于Mie散射理论和低浓度近似,对磷化镓光子晶体的安德森定域化进行了理论计算,并分析了影响定域化参量的各种因素。结果表明,在浓度为10%,折射率比值大于3.8,无吸收状态下,中红外区出现了安德森定域化现象,并且随粒子半径的增大,定域化区向长波段移动,且基质折射率的增大使定域化现象减弱。研究结果为该类晶体的定域化现象提供了理论参考。 相似文献
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根据Mie散射理论,在低浓度近似下,对中红外区由金属氧化物构成的反蛋白石光子晶体的禁带的存在区域,即光子定域化区进行了研究。发现在浓度为10%,此类晶体在中红外区将出现多个光子禁带区域,并且计算了影响定域化区域的各种因素。由此可知利用材料在剩余射线带内折射率小于1的特性,我们可以制备出中红外区和远红外区存在禁带的光子晶体。这一结果为反蛋白石晶体的研究提供了理论方法。 相似文献
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本文根据Mie散射理论和低浓度近似下,对在中红外区高折射率半导体材料AlP等做为散射体的类Opal光子晶体的安德森定域化进行了理论研究,发现在浓度为10%,折射率比值大于3.8,无吸收状态下,此类晶体将出现两个定域化区.同时为此类晶体的定域化研究提供了一个比较理想的处理方法. 相似文献
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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 相似文献
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M. V. Vasnetsov V. A. Pas’ko T. N. Orlova D. A. Plutenko A. D. Kudryavtseva N. V. Tcherniega 《Journal of Experimental and Theoretical Physics》2018,126(5):579-591
The Bragg diffraction in synthetic opal as a 3D photonic crystals has been analyzed using the weak disorder model in various approximations. For a one-domain crystal, the photonic bandgap is calculated in the regime of reflection along the 〈111〉 axis. In the multidomain case, a considerable expansion of the photonic bandgap, the emergence of asymmetry, and the photon band shift to the short-wavelength region are demonstrated. The results are compared with experimental dependences. 相似文献
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Shao-Wei Wang Wei Lu Xiao-Shuang Chen Mei Zhou Xue-Chu Shen 《International Journal of Infrared and Millimeter Waves》2003,24(6):963-971
Photonic band gap (PBG) in two-dimensional (2D) anisotropic photonic crystal (PC) constructed of rectangular bars has been numerically studied by using Transfer Matrix Method (TMM). The results show that the PBG is bounded by the lower band edge of TE wave and the upper band edge of TM wave. Its width simply increases with increasing of shape parameter . It reaches a maximum value as the structure degenerates into its 1D counterpart, due to the complete overlapping of gaps in TE and TM waves. The anisotropy in PC structure results in the transmission anisotropic property. One can design the PBG structures in different incident directions to match their application demand. 相似文献
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异质镜像光子晶体的光子带隙研究 总被引:1,自引:0,他引:1
对异质镜像结构光子晶体(ABCCBA)N进行了研究。首先,利用一维介电体系中处理光传播的方法--传输矩阵法,详细推导了异质镜像光子晶体透射率的计算公式;然后,采用Matlab软件编程仿真并分析了光子带隙形成与镜像周期数目、光子带隙数目与光子晶体薄层厚度、光子带隙位置与入射角大小等的关系。结果表明:光子带隙的形成及变化主要受光子晶体薄层厚度及入射角大小变化的影响。通过改变影响光子晶体光子带隙的参数,可得到不同频段的光子带隙,用来制作高质量反射镜、滤波器和发光二极管等。 相似文献
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Photonic Band Gap Structures with Periodically Arranged Atoms in a Two-Dimensional Photonic Crystal 下载免费PDF全文
Linear transmission, reflection and absorption spectra for a new two-dimensional photonic crystal with periodically arranged resonant atoms are examined. Numerical results show that a twin-gap structure with forbidden bands displaced from a non-doped bandgap structure can be produced as a result of atomic polarization. The absorption spectrum is also significantly altered compared to the single atom entity. 相似文献
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Three-dimensional SiO2 photonic crystals (PhCs) are fabricated on quartz substrates by the vertical deposition method. Scanning electron microscopy measurement reveals that the samples exhibit an ordered close-packed arrangement of SiO2 spheres. It is found that the position of the [111] photonie band gap (PBG) shifts to a long wavelength (red shift) with increasing sphere size. Gap broadening effects are observed due to the presence of defects in the samples. Moreover, the optical properties of the PBG are very sensitive to the annealing temperature. Our results indicate that the optical properties of the PBG can be easily tuned in the visible region by appropriate experimental parameters, which will be useful for practical applications of PhC optical devices. 相似文献
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We developed photochemically controlled photonic crystals which may be useful in novel recordable and erasable memories and/or
display devices. These materials can operate in the UV, visible or near IR spectral regions. Information is recorded and erased
by exciting the photonic crystal with ∼ 360 nm UV light or ∼ 480 nm visible light. The recorded information is read out by
measuring the photonic crystal diffraction wavelength. The active element of the device is an azobenzene functionalized hydrogel
which contains an embedded crystalline colloidal array. UV excitation forms cis-azobenzene while visible excitation forms
trans-azobenzene. Larger dipole moment of the cis-form results in decrease of the free energy of mixing which causes the hydrogel
to swell and to red-shift the photonic crystal diffraction with a 36 s time constant. We also observed fast ms and sub-ms
transient dynamics associated with convection due to heating of the medium by UV excitation. Convective motion of the medium
stretches the PCCA for about 6 μs within which the convection decays and the elastic restoring force of the PCCA brings back
the stretched PCCA to its equilibrium state with 33 μs time constant.
Paper presented at the 2nd International Conference on Ionic Devices, Anna University, Chennai, India, Nov. 28–30, 2003. 相似文献