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1.
In this paper, by means of the network equation and generalized dimensionless Floquet-Bloch theorem, we study the influences of the number of connected waveguide segments (NCWS) between adjacent nodes and the matching ratio of waveguide length (MRWL) on the photonic bands generated by quadrangular multiconnected networks (QMNs), and obtain a series of formulae. It is found that multicombining networks (MCNs) and repetitive combining networks (RCNs) are equivalent to each other and they can all be simplified into the simplest fundamental combining systems. It would be useful for adjusting the number, widths, and positions of photonic bands, and would possess potential applications for the designing of all-optical devices and photonic network devices. 相似文献
2.
Photonic band structures of two-dimensional photonic crystals with deformed lattices 总被引:2,自引:0,他引:2 下载免费PDF全文
Using the plane-wave expansion method, we have calculated and analysed the
changes of photonic band structures arising from two kinds of deformed
lattices, including the stretching and shrinking of lattices. The square
lattice with square air holes and the triangular lattice with circular air
holes are both studied. Calculated results show that the change of lattice
size in some special ranges can enlarge the band gap, which depends strongly
on the filling factor of air holes in photonic crystals; and besides, the
asymmetric band edges will appear with the broken symmetry of lattices. 相似文献
3.
J. Čtyroký S. Helfert R. Pregla P. Bienstman R. Baets R. De Ridder R. Stoffer G. Klaasse J. PetráČek P. Lalanne J. P. Hugonin R. M. De LaRue 《Optical and Quantum Electronics》2002,34(5-6):455-470
Modal reflection, transmission and loss of deeply etched Bragg waveguide gratings were modelled by six European laboratories
using independently developed two-dimensional (2D) numerical codes based on four different methods, with very good mutual
agreement. It was found that (rather weak) material dispersion of the SiO2/Si3N4 system does not significantly affect the results. The existence of lossless Floquet-Bloch modes in deeply etched gratings
was confirmed. Based on reliable numerical results, the physical origin of out-of-plane losses of 1D or 2D photonic band gap
structures in slab waveguides is briefly discussed. 相似文献
4.
J. Čtyroký S. Helfert R. Pregla P. Bienstman R. Baets R. De Ridder R. Stoffer G. Klaasse J. Petráček P. Lalanne J.-P. Hugonin R.M. De La Rue 《Optical and Quantum Electronics》2002,34(5):455-470
Modal reflection, transmission and loss of deeply etched Bragg waveguide gratings were modelled by six European laboratories using independently developed two-dimensional (2D) numerical codes based on four different methods, with very good mutual agreement. It was found that (rather weak) material dispersion of the SiO2/Si3N4 system does not significantly affect the results. The existence of lossless Floquet–Bloch modes in deeply etched gratings was confirmed. Based on reliable numerical results, the physical origin of out-of-plane losses of 1D or 2D photonic band gap structures in slab waveguides is briefly discussed. 相似文献
5.
6.
The tunable two-dimensional photonic crystals band gap, absolute photonic band gap and semi-Dirac point are beneficial to designing the novel optical devices. In this paper, tunable photonic band gaps structure was realized by a new type two-dimensional function photonic crystals, which dielectric constants of medium columns are functions of space coordinates. However for the two-dimensional conventional photonic crystals the dielectric constant does not change with space coordinates. As the parameter adjustment, we found that the photonic band gaps structures are dielectric constant function coefficient, medium columns radius, dielectric constant function form period number and pump light intensity dependent, namely, the photonic band gaps position and width can be tuned. we also obtained absolute photonic band gaps and semi-Dirac point in the photonic band gaps structures of two-dimensional function photonic crystals. These results provide an important theoretical foundation for design novel optical devices. 相似文献
7.
8.
Extreme narrow photonic passbands generated from defective two-segment-connected triangular waveguide networks 下载免费PDF全文
In this paper, we investigate the optical transmission properties of perfect and defective two-segment-connected tri- angular waveguide networks (2SCTWNs) and find that after introducing defects in networks, many groups of transparent extreme narrow photonic passbands (ENPPs) will be created in the middle of the transmission spectra, the number for each group and the group number of ENPPs can he adjusted by the matching ratios of waveguide length (MRWLs), the number of defects, and the number of unit cells of 2SCTWNs. The influences of MRWL, number of defects, and number of unit cells on the number, width, and position of these ENPPs are researched and a series of quantitative rules and prop- erties are obtained. It may be useful for the designing of high-sensitive optical switches, wavelength division multiplexers, extreme-narrowband filters, and other correlative waveguide network devices. 相似文献
9.
10.
The polarization-dependent photonic band gaps (TM and TE polarizations) in two-dimensional photonic crystals with square lattices
composed of air holes in dielectric and vice versa i.e., dielectric rods in air, using the plane-wave expansion method are investigated. We then study, how the photonic band
gap size is affected by the changing ellipticity of the constituent air holes/dielectric rods. It is observed that the size
of the photonic band gap changes with changing ellipticity of the constituent air holes/dielectric rods. Further, it is reported,
how the photonic band gap size is affected by the change in the orientation of the constituent elliptical air holes/dielectric
rods in 2D photonic crystals. 相似文献
11.
Photonic band structure of three-dimensional colloidal crystals with field-induced lattice structure transformation 下载免费PDF全文
By utilizing the electrorheological effect,
three-dimensional colloidal crystals can be produced, whose lattice
structure can be changed from the body-centered-tetragonal lattice
to other lattices under the application of electric fields. This
paper calculates photonic band structures of such crystals with
lattice structure transformation, and demonstrates the existence of
complete band gaps for some intermediate lattices. Thus, it becomes
possible to use the electrorheological effect to achieve photonic
crystals with desired photonic gap properties resulting from tunable
structures. 相似文献
12.
手征材料构成的简立方光子晶体光子带结构计算——平面波法 总被引:7,自引:3,他引:7
发展了适于计算由手征材料组成的光子晶体的光子带结构的平面波法。在此基础上,研究了由手征材料组成的简立方光子晶体的光子带结构。计算表明:手征材料“球形原子”在电介质中排列所组成的科立方光子晶体和电介质“球形原子”在手征材料中排列所组成的简立方光子晶体,不仅都存在光子带隙,而且存在截止频率,在该频率以下的区域无传播模存在,本语文认了这种光子晶体的潜在应用。 相似文献
13.
A ministop band in a single-defect photonic crystal waveguide based on silicon on insulator 下载免费PDF全文
This paper reports that a two-dimensional single-defect photonic crystal waveguide in the Г-K direction with triangular lattice on a silicon-on-insulator substrate is fabricated by the combination of electron beam lithography and inductively coupled plasma etching. A ministop band (MSB) is observed by the measurement of transmission characteristics. It results from the coupling between the two modes with the same symmetry, which is analysed from the stimulated band diagram by the effective index and the two-dimensional plane wave expansion methods. The parameter working on the MSB is the ratio of the radius of air holes to the lattice constant, fla. It is obtained that the critical τ/a value determining the occurrence or disappearance of MSB is 0.36. When τ/a is larger than or equal to 0.36, the MSB occurs. However, when τ/a is smaller than 0.36, the MSB disappears. 相似文献
14.
A ministop band in a single-defect photonic crystal waveguide based on silicon on insulator 下载免费PDF全文
This paper reports that a two-dimensional single-defect photonic
crystal waveguide in the \textit{$\Ga$-K} direction with triangular
lattice on a silicon-on-insulator substrate is fabricated by the
combination of electron beam lithography and inductively coupled
plasma etching. A ministop band (MSB) is observed by the measurement
of transmission characteristics. It results from the coupling
between the two modes with the same symmetry, which is analysed from
the stimulated band diagram by the effective index and the
two-dimensional plane wave expansion methods. The parameter working
on the MSB is the ratio of the radius of air holes to the lattice
constant, $r/a$. It is obtained that the critical $r/a$ value
determining the occurrence or disappearance of MSB is 0.36. When
$r/a $ is larger than or equal to 0.36, the MSB occurs. However,
when $r/a $ is smaller than 0.36, the MSB disappears. 相似文献
15.
三角形复式晶格的光子带结构研究 总被引:7,自引:2,他引:7
设计了一种三角形复式晶格结构的光子晶体,在该类晶体中,电介质圆柱在空气中的排列存在E偏振和H偏振的光子带隙重叠区,称之为绝对光子带隙;而空气圆孔在电介质中的排列时,虽然E偏振和H偏振均分别存在光子带隙,但不存在绝对光子带隙。同时利用晶体的光子带结构研究了有效长波介电常数,所得结果与静电理论吻合。 相似文献
16.
采用一种新的平面波展开法研究金属光子晶体的带结构,即在传统平面波展开法的基础上,将“原问题”拓展,引入一个“新问题”,通过求解“新问题”得到“原问题”的带结构,并论证了它们之间的关系.为了准确求解“新问题”,引入辅助函数,将其色散关系等价为一个积分微分本征方程,求解这个本征方程得到“新问题”的带结构,从而由此导出“原问题”的带结构.最后,以正方晶格二维金属光子晶体为例,进行数值计算,得到了满意的结果.
关键词:
金属光子晶体
平面波展开法
带结构
正方晶格 相似文献
17.
18.
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
19.
20.
A review is presented of various composite structures containing double-negative metamaterials or two types of single-negative metamaterials. In particular, non-Bragg band gaps arising from phase-compensation or tunneling effects and their manipulation of light are stressed. The non-Bragg band gaps that are robust against incident directions, thickness randomness and are easily tuned by changing the structural parameters can not only expand our ability in controlling the flow of light, but also provide new mechanisms for the design of photonic devices. 相似文献