共查询到20条相似文献,搜索用时 62 毫秒
1.
Adam Rudziński Anna Tyszka-Zawadzka Paweł Szczepański 《Optical and Quantum Electronics》2007,39(4-6):501-510
The aim of this paper is to present the analysis of influence of defects in 1D photonic crystal (PC) on the density of states
and simultaneously spontaneous emission, in both spatial and frequency domains. In our investigations we use an analytic model
of 1D PC with defects. Our analysis reveals how presence of a defect causes a defect mode to appear. We show that a defect
in 1D PC has local character, being negligible in regions of PC situated far from the defected elementary cell. We also analyze
the effect of multiple defects, which lead to photonic band gap splitting. 相似文献
2.
We have experimentally observed the eigenmode splitting due to coupling of the evanescent defect modes in three-dimensional photonic crystals. The splitting was well explained with a theory based on the classical wave analog of the tight-binding (TB) formalism in solid state physics. The experimental results were used to extract the TB parameters. A new type of waveguiding in a photonic crystal was demonstrated experimentally. A complete transmission was achieved throughout the entire waveguiding band. We have also obtained the dispersion relation for the waveguiding band of the coupled periodic defects from the transmission-phase measurements and from the TB calculations. 相似文献
3.
We analyze the properties of magneto-optical defect states in two-dimensional photonic crystals. With out-of-plane magnetization, the magneto-optical coupling splits doubly-degenerate TE states into two counter-rotating modes at different frequencies. The strength of magneto-optical coupling strongly depends on the spatial overlap of the cavity domain structures and the cross product of the modal fields. The transport property of the resultant nonreciprocal states is demonstrated in a junction circulator structure with a magneto-optical cavity coupled to three waveguides. By a proper matching of the magneto-optical frequency splitting with the cavity decay rate into the waveguide, ideal three-port circulator characteristics with complete isolation and transmission can be achieved, with an operational bandwidth proportional to the magneto-optical constant. The proposed optical circulator in a bismuth-iron-garnet/air photonic crystal is demonstrated with finite-difference time-domain calculations and is compared to an alternative implementation of silicon/air crystal infiltrated with a single bismuth-iron-garnet domain. 相似文献
4.
Optical properties of 2D nanocomposite-based photonic crystals with a lattice defect are studied. The nanocomposite comprises metallic nanospheres dispersed in a transparent matrix and is characterized by an effective resonant permittivity. Transmission spectrum for s-polarized waves at oblique incidence is calculated. Spectral manifestation of the splitting of the defect mode when its frequency coincides with the resonant frequency of the nanocomposite is studied. The essential dependence of the splitting on the angle of incidence and concentration of metallic nanospheres in the nanocomposite matrix is established. Specific features of spatial distribution of the electric field intensity in defect modes of crystals are analyzed. 相似文献
5.
Using three-dimensional time-domain numerical simulations of the nonlinear dispersive Maxwell equations for a defect microcavity in a photonic crystal wire, we show that the transmission through the bandgap can be all-optically modulated via the generation of transient states associated with the nonlinear splitting of the defect mode. Analytical results based on time-domain coupled-mode theory are derived as well. 相似文献
6.
以二维三角晶格光子晶体为研究对象,在该光子晶体中引入两行以一行耦合介质柱为间距的平行单模线缺陷波导.通过分析和研究光子晶体波导耦合结构的耦合和解耦合特性,发现在不同频率下耦合波导的耦合长度不同.利用平面波展开法和定向耦合原理计算了在不同入射光频率下,缺陷波导间耦合波导的耦合长度,设计了一种新型超微光子晶体波导耦合型三波长功分器,实现了归一化频率分别为0.369、0.394、0.435的光波的分束效果.采用时域有限差分法验证了该功分器具有很好的功率分配效果.本文结果有助于光子晶体新型滤波器、定向耦合器、波分复用器、偏振光分束器以及光开关等光子器件的研究. 相似文献
7.
Hong Wang YSheng Luo Yong-Tao Wang Hong-Bing Zhang Yun-Tuan Fang 《Physica B: Condensed Matter》2011,406(15-16):2977-2981
Using the 4×4 transfer matrix method, we investigate the splitting of defect-modes in one-dimensional magnetic photonic crystal. Numerical results exhibit defect-mode splitting in the presence of external magnetic fields. The splitting condition has been examined. The results show that defect-mode splitting critically depends on the magneto-optical gyrotropy factor and number of layers. We predict theoretically that magnetic photonic crystal consisting of gyrotropic material can be used as a tunable filter. 相似文献
8.
利用传输矩阵法研究了表层厚度渐变的一维非对称耦合腔光子晶体的反射相位特性. 研究表明, 光子禁带内(包括缺陷模附近)的反射率在98%以上, 且基本不受表层厚度影响, 特别是, 在非正入射情况下, 简并的缺陷模随着表层厚度的变化会发生分裂; 进一步研究发现, 在缺陷模分裂处附近, TE, TM偏振的反射相位以及它们之间的相位差均敏感地依赖于表层厚度的变化, 从而使得反射光的偏振态也随表层厚度的变化而敏感变化, 其物理机理在于缺陷模分裂所造成的剧烈相位变化. 基于上述特性, 设计了一种表层厚度呈二维周期变化的一维光子晶体结构, 从该结构反射的激光经透镜聚焦后, 在聚焦区域同时存在各种偏振态(包括沿不同方向的线偏振、左旋或右旋圆偏振、椭圆偏振等)的子光束, 它们叠加后在聚焦区域将产生具有无规相位和无规偏振态的光场. 以上结果能有效降低激光的相干性, 在激光核聚变等领域有潜在的应用价值. 相似文献
9.
10.
Polarization splitting filter characteristics of Au-filled high-birefringence photonic crystal fiber
Y. Du S.-G. Li S. Liu X.-P. Zhu X.-X. Zhang 《Applied physics. B, Lasers and optics》2012,109(1):65-74
Polarization splitting wavelength-selective characteristics of Au-filled high-birefringence photonic crystal fiber (HB-PCF) based on the finite element method is investigated. Numerical results show that the polarization splitting effect can be observed in metal-filled HB-PCF. The resonances points and strength in two polarizations can be adjusted by changing the fiber birefringence, the pitch between the adjacent air holes and the size of the metal wires. Finally, two kinds of Au-filled HB-PCFs with completely polarization splitting and filtering characteristics in communication wavelength are designed. Results show that this polarization splitting effect in metal-filled HB-PCF is very useful for further studies in polarization-dependent wavelength-selective applications and other fiber-based plasmonic devices. 相似文献
11.
Spectral properties of a one-dimensional photonic crystal with a resonant defect nanocomposite layer
S. Ya. Vetrov A. Yu. Avdeeva I. V. Timofeev 《Journal of Experimental and Theoretical Physics》2011,113(5):755-761
The spectral properties of a one-dimensional photonic crystal with a defect nanocomposite layer that consists of metallic
nanoballs distributed in a transparent matrix and is characterized by an effective resonance permittivity are studied. The
problem of calculating the transmission, reflection, and absorption spectra of p-polarized waves in such structures is solved for oblique incidence of light, and the spectral manifestation of defect-mode
splitting as a function of the volume fraction of nanoballs and the structural parameters is studied. The splitting is found
to depend substantially on the nanoball concentration in the defect, the defect layer thickness, and the angle of incidence.
The angle of incidence is found at which the resonance frequency of the nanocomposite is located near the edge of the bandgap
or falls in the frequency region of a continuous spectrum. The resonance situation appearing in this case results in an additional
transmission band or an additional bandgap in the transmission spectrum. 相似文献
12.
S. Ya. Vetrov A. Yu. Avdeeva R. G. Bikbaev I. V. Timofeev 《Optics and Spectroscopy》2012,113(5):517-521
Spectral properties of a 1D photonic crystal that is comprised of two multilayered dielectric mirrors and a nanocomposite layer between them as a structural defect are studied. The nanocomposite consists of silver nanoballs dispersed in a transparent matrix and is characterized by an effective resonant permittivity. The spectral manifestation of the defect mode splitting for the s-polarized waves is studied as a function of the angle of incidence and concentration of nanoballs. Specific features of the transmission spectra for the s- and p-polarized waves are established for the angle of incidence equal to the Brewster angle of the seeding photonic crystal. It is shown, in particular, that, in the region of the continuous transmission spectrum of the spolarized waves, there arises an additional bandgap caused by mixing of the resonant mode with photonic modes. 相似文献
13.
Based on a one-dimensional magnetic photonic crystal made of magneto-optic material, a tunable double-channel filter is presented. The tunability of such a filter can be achieved by defect mode splitting in the presence of external magnetic fields. Using the 4×4 transfer matrix method, the influences of the structural and compositional parameters are also analyzed, such as the magneto-optical effect, number of layers and angle of incidence. 相似文献
14.
Wavelength-selective characteristics of high birefringence photonic crystal fiber with Au nanowires selectively filled in the cladding air holes 下载免费PDF全文
Filter characteristics of a designed gold-filled high birefringence photonic crystal fiber are investigated based on the finite element method. The wavelength filter resonances in the high birefringence photonic crystal fiber occur at different points for different polarized directions, and the resonance strength in the x-polarized case is much weaker than that in the y-polarized case. The much more obvious splitting filter characteristics and different resonance strength imply the study and application values in splitting and single polarization fiber devices. The simulation results show that increasing the number of the gold wires only enhances the resonance strength when there is no surface plasmon supermode formed. With the diameters of the gold wires increasing, the response wavelength moves to a longer wavelength, and the strength becomes stronger. When the diameter is increased to 1.4 μm, the response wavelength in the x-polarized case can be tuned to 1.318 μm, which is the communication wavelength. The strongest resonance occurs at 1.2375 μm in the y-polarized case, and the peaking loss can reach 435.83 dB/cm. 相似文献
15.
16.
Noama Ouchani Abdelaziz El Moussaouy Hassan Aynaou Youssef El Hassouani El Houssaine El Boudouti Bahram Djafari-Rouhani 《Physics letters. A》2018,382(4):231-240
We investigate theoretically the possibility to control the optical transmission in the visible and infrared regions by a defective one dimensional photonic crystal formed by a combination of a finite isotropic superlattice and an anisotropic defect layer. The Green's function approach has been used to derive the reflection and the transmission coefficients, as well as the densities of states of the optical modes. We evaluate the delay times of the localized modes and we compare their behavior with the total densities of states. We show that the birefringence of an anisotropic defect layer has a significant impact on the behavior of the optical modes in the electromagnetic forbidden bands of the structure. The amplitudes of the defect modes in the transmission and the delay time spectrum, depend strongly on the position of the cavity layer within the photonic crystal. The anisotropic defect layer induces transmission zeros in one of the two components of the transmission as a consequence of a destructive interference of the two polarized waves within this layer, giving rise to negative delay times for some wavelengths in the visible and infrared light ranges. This property is a typical characteristic of the anisotropic photonic layer and is without analogue in their counterpart isotropic defect layers. This structure offers several possibilities for controlling the frequencies, transmitted intensities and the delay times of the optical modes in the visible and infrared regions. It can be a good candidate for realizing high-precision optical filters. 相似文献
17.
通常采用含两个耦合参数的紧束缚近似,就能很好地描述光子晶体缺陷因耦合而导致的共振频率分裂.然而,缺陷耦合造成的共振频率移动,即包含奇数个缺陷的耦合系统的中央共振频率位置与原来单缺陷时的共振频率位置存在差异,则只有采用含三个耦合参数的严格紧束缚方法才能正确描述.根据耦合参数与共振频率的关系,利用三缺陷耦合系统的模拟计算结果确定了三个耦合参数的具体值,从而在理论上能够预言由任意个缺陷构成的耦合系统的共振频率的移动和分裂.理论预言与基于有限时域差分法的数值计算完全相符. 相似文献
18.
含色散介质的一维光子晶体微腔中简正耦合模的物理图像 总被引:1,自引:1,他引:0
对一维光子晶体中的色散介质采用洛伦兹振子模型,对线性层及色散δ层均采用传输矩阵的方法,研究了一维含色散介质的光子晶体微腔中的简正耦合模.通过改变洛伦兹振子和微腔之间的失谐频率,分析了简正耦合模频率的变化情况.在失谐频率比较大时,光与洛仑兹振子间的耦合作用较小,简正耦合模中的一个接近腔模频率,而另一个则接近洛仑兹振子的共振频率;在失谐频率比较小时,光与洛仑兹振子间的耦合作用较大,简正耦合模与未耦合的腔模频率和洛仑兹振子的共振频率之间的差别较为明显.最后通过引进该结构的复有效折射率,对含色散介质的系统,由于带隙中间的共振模被湮灭并分裂为左右两个耦合模,其复有效折射率虚部在原共振峰处跃变为一较大值,而在新生成的两个耦合模附近趋近于零,光与色散介质相互耦合而形成的腔极化激元的物理图像十分清晰. 相似文献
19.
将石墨烯中赝磁场的产生机理运用于光子石墨烯,通过在光子石墨烯中引入晶格有规律单轴形变的方式,理论分析得到了谷依赖的均匀赝磁场,并通过数值模拟的方法观察到明显的谷霍尔效应.这种谷霍尔效应的显著程度随晶格形变度的增加而加强.在具有一定损耗的电介质材料构成的形变光子石墨烯中仍可观察到明显的谷霍尔效应.随着电介质材料损耗的增加,谷霍尔效应导致的波束转弯效果依然能够保持,只是强度逐渐变弱.类似于自旋电子学中的自旋霍尔效应,这种光子石墨烯中等效赝磁场作用下的谷霍尔效应在未来谷极化器件的设计和应用中具有重要意义. 相似文献
20.
A one-to-two splitter for self-collimated beams in photonic crystal (PC) is designed by inserting one row of line defects. Finite-difference time-domain (FDTD) method is used to simulate the light propagation process. Our systematical studies show that the splitting ratio is a function of the airholes size of the line defect radius, and stays fairly constant as a function of frequency. Furthermore, it is shown the numerical results can be analyzed by coupled-mode theory. 相似文献