共查询到20条相似文献,搜索用时 47 毫秒
1.
The properties of unusual transmission as a function of the dissipation factor in single-negative (SNG) materials are theoretically investigated. Using Drude-like expressions for the permittivity in epsilon-negative (ENG) material and the permeability in mu-negative (MNG) material, we investigate the angular dependence of unusual transmission for both transversal electric (TE) and transversal magnetic (TM) waves. Two model structures, a single ENG layer and an ENG–MNG bilayer, are examined. A very different dependence of the incident angle on the transmission is found for these two structures. A discussion of the effect of the polarization of incident waves is also given. 相似文献
2.
Numerical simulations of negative-index refraction in a lamellar composite with alternating single negative layers 下载免费PDF全文
Negative-index refraction is demonstrated in a lamellar composite with
epsilon-negative (ENG) and mu-negative (MNG) materials stacked alternatively. Based
on the effective medium approximation, simultaneously negative effective
permittivity and permeability of such a lamellar composite are obtained
theoretically and further proven by full-wave simulations. Consequently, the
renowned left-handed metamaterial comprising split ring resonators and wires is
interpreted as an analogy of such ENG--MNG layers. In addition, beyond the
effective medium approximation, the propagating field squeezed near the ENG/MNG
interface is demonstrated to be left-handed surface waves with backward phase
velocity. 相似文献
3.
Wei-Hsiao Lin Chien-Jang Wu Shoou-Jinn Chang 《Applied Physics A: Materials Science & Processing》2011,104(3):807-809
In this work, we investigate the angular dependence of transmission and reflection in the single-negative (SNG) materials.
We consider a model structure of a SNG bilayer which consists of the epsilon-negative (ENG) and mu-negative (MNG) layers.
The wave transmission and reflection properties due to the losses from the ENG and MNG materials are specifically investigated.
With the presence of losses in the ENG and MNG materials, some unusual wave properties will be explored and numerically demonstrated. 相似文献
4.
We present an overview of recent advances within the field of slow- and stopped-light in metamaterial and plasmonic waveguides. We start by elucidating the mechanisms by which these configurations can enable complete stopping of light. Decoherence mechanisms may destroy the zero-group-velocity condition for real-frequency/complex-wavevector modes, but we show that metamaterial and nanoplasmonic waveguides also support complex-frequency/real-wavevector modes that uphold the light-stopping condition. A further point of focus is how, by using gain, dissipative losses can be overcome in the slow- and stopped-light regimes. To this end, on the basis of full-wave finite-difference time-domain (FDTD) simulations and analytic transfer-matrix calculations, we show that the incorporation of thin layers made of an active medium, placed adjacently to the core layer of a negative-refractive-index waveguide, can fully remove dissipative losses – in a slow- or stopped-light regime where the effective index of the guided lightwave remains negative. 相似文献
5.
The transmission properties of one-dimensional (1D) photonic crystals containing two kinds of single-negative (ENG and MNG) material are investigated theoretically. A type of photonic gap with zero effective phases (zero-φeff) and the effects of absorption on the properties of the zero-φeff gap were shown. Specifically, it is demonstrated that strong absorption creates photon states inside the gap and this makes the band gap to be of zero width. 相似文献
6.
A modified planar waveguide made of a metamaterial with negative permittivity and permeability has been considered. The modification of the waveguide by the introduction of an air channel qualitatively changes its dispersion characteristics due to the appearance of an ultraslow mode. The fields and properties of this mode have been investigated. The mode has been shown to be similar to a surface plasmon. In addition, it has been shown that the plasmons can propagate in subwavelength waveguides. Such ultraslow plasmons can be used in plasmonics and microwave and accelerator techniques. 相似文献
7.
J. Silva-Valencia A. M. C. Souza 《The European Physical Journal B - Condensed Matter and Complex Systems》2012,85(1):5
The properties of the wave transmission in the lossy single-negative (SNG) metamaterials
are experimentally investigated. The model structure of lossy epsilon-negative (ENG)
monolayer and SNG bilayer consisting of a lossy ENG material and a mu-negative (MNG) are
considered in this work. Simulation and experimental results show that the transmittance
of the lossy SNG materials can be enhanced by two approaches, increasing dissipation
coefficient and increasing the thickness of the lossy SNG. The lossy ENG material is
physically fabricated by using composite right- and left-handed transmission lines grafted
with radiation unit cell. The experimental results are in very good agreement with the
previous theoretical analysis. 相似文献
8.
A modified planar waveguide made of a metamaterial with negative permittivity and permeability has been considered. The modification
of the waveguide by the introduction of an air channel qualitatively changes its dispersion characteristics due to the appearance
of an ultraslow mode. The fields and properties of this mode have been investigated. The mode has been shown to be similar
to a surface plasmon. In addition, it has been shown that the plasmons can propagate in subwavelength waveguides. Such ultraslow
plasmons can be used in plasmonics, microwave and accelerator techniques. 相似文献
9.
提出了一种基于单负Metamaterials对的带通滤波器的设计原理,给出了这种带通滤波器的谐振频率的表达式,对其谐振频率及带宽与其决定因素之间的关系进行了计算,对计算结果进行了讨论,为设计单负Metamaterial对带通滤波器的理论与方法提供了依据。研究结果表明:利用单负Metamaterials对的确可以实现带通滤波器;ENG板的磁导率μ1、MNG板的介电常数ε2、电等离子体频率ωep、磁等离子体频率ωmp、两个层的厚度比值a这五个因素决定了这种滤波器的中心频率;两个层的厚度及二者之间的比值决定这种滤波器的带宽。 相似文献
10.
D. V. Guzatov V. V. Klimov N. S. Poprukailo 《Journal of Experimental and Theoretical Physics》2013,116(4):531-540
Analytical expressions for the rate of spontaneous emission from a chiral (optically active) molecule located near a half-space occupied by a chiral (bi-isotropic) material have been obtained and analyzed in detail. It is established that the rates of spontaneous emission from the “right” and “left” enantiomers of molecules occurring near the chiral medium may significantly differ in cases of chiral materials with (i) both negative dielectric permittivity and magnetic permeability (DNG metamaterial) and (ii) negative permeability and positive permittivity (MNG metamaterial). Based on this phenomenon, DMG and MNG metamaterials can be used to create devices capable of separating right and left enantiomers in racemic mixtures. 相似文献
11.
Liwei Zhang Guiqiang Du Yewen Zhang 《Applied Physics A: Materials Science & Processing》2012,109(4):851-856
We present a theoretical investigation into the energy transport and transient wave propagation in metamaterial tunneling structures consisting of ??-negative (ENG) and ??-negative (MNG) materials. It is proved that a conjugated matched ENG/MNG bilayer and a (zero-index-material doped) photonic crystal heterostructure can work as a sub-wavelength resonator at tunneling frequency. The tunneling modes need a certain time to achieve the steady state and the charge up characteristic time increases (nearly) exponentially with the thickness of the structures. Under the steady state, the wave in the single-negative-material structures is not evanescent, but a hybrid of a traveling wave and a reactive standing wave. The phase difference between the electric field and the magnetic field varies with the position and time. The investigation of transient wave propagation in the metamaterial tunneling structures will help us to understand the interaction process between wave and metamaterial and to design special functional apparatus. 相似文献
12.
13.
L. Nickelson A. Bubnelis S. Asmontas 《Applied Physics A: Materials Science & Processing》2012,109(4):877-881
Here, we present the phase constant dependencies of propagating eigenmodes of an open cylindrical anisotropic metamaterial waveguide when the metamaterial permittivity and permeability tensor components may accept values close or equal to zero. Dispersion characteristics of rod and hollow-core waveguides with the radii 0.5, 2.5, and 5 mm at the left-handed polarization of the microwave are shown here. There are unusual shapes of eigenmode dispersion characteristics and anomalous sectors of the characteristics at certain frequencies. The first eigenmode of the rod waveguide with the lowest cutoff frequency is a particularly important mode because it is a single one in the frequency range 1.0?C1.9 GHz, and some small variations on the frequency produce large changes in the phase constant. We can observe packages of dispersion characteristic branches when their cutoff frequencies closed to the metamaterial electric and magnetic plasma frequencies between 1.9 and 3.5 GHz. There are only three modes in the hollow core anisotropic metamaterial waveguide at the frequency range 1.4?C2.8 GHz. 相似文献
14.
Engineering optical gradient force from coupled surface plasmon polariton modes in nanoscale plasmonic waveguides 下载免费PDF全文
We explore the dispersion properties and optical gradient forces from mutual coupling of surface plasmon polariton(SPP) modes at two interfaces of nanoscale plasmonic waveguides with hyperbolic metamaterial cladding.With Maxwell's equations and Maxwell stress tensor,we calculate and compare the dispersion relation and optical gradient force for symmetric and antisymmetric SPP modes in two kinds of nanoscale plasmonic waveguides.The numerical results show that the optical gradient force between two coupled hyperbolic metamaterial waveguides can be engineered flexibly by adjusting the waveguide structure parameters.Importantly,an alternative way to boost the optical gradient force is provided through engineering the hyperbolic metamaterial cladding of suitable orientation.These special optical properties will open the door for potential optomechanical applications,such as optical tweezers and actuators. 相似文献
15.
Lamellar model of the left-handed metamaterials composed of metallic split-ring resonators and wires
Left-handed materials composed of split ring resonators (SRRs) and wires are investigated in the viewpoint of lamellar composite with epsilon-negative (ENG) and mu-negative (MNG) materials staked alternatively. Several configurations of the SRR-wire metamaterial are numerically simulated to confirm its left-handed response as an analogy to the ENG-MNG lamellar model. 相似文献
16.
Nanoscale slot waveguides of hyperbolic metamaterials are proposed and demonstrated for achieving large optical field enhancement. The dependence of the enhanced electric field within the air slot on waveguide mode coupling and permittivity tensors of hyperbolic metamaterials is analyzed both numerically and analytically. Optical intensity in the metamaterial slot waveguide can be more than 25 times stronger than that in a conventional silicon slot waveguide, due to tight optical mode confinement enabled by the ultrahigh refractive indices supported in hyperbolic metamaterials. The electric field enhancement effects are also verified with the realistic metal-dielectric multilayer waveguide structure. 相似文献
17.
A. B. Manenkov P. G. Gerolymatos I. G. Tigelis 《Radiophysics and Quantum Electronics》2010,53(3):191-200
We use a variational method to study the problem of reflection of a guided mode from an abruptly terminated planar dielectric
waveguide made of a metamaterial. The theory is illustrated by problems of abruptly terminated three-layer waveguides with
piecewise-constant and variable permittivity profiles. Differences in the scattering characteristics for systems with metamaterials
and conventional media are discussed. 相似文献
18.
A. B. Manenkov 《Optical and Quantum Electronics》2017,49(8):268
The problem of guided TM mode reflection from an abruptly terminated planar metamaterial waveguide is studied using a variational technique. The theory is illustrated by examples of abruptly terminated three-layer waveguides with step profiles of permittivity and permeability. The influence of media losses on reflectivity characteristics is considered. 相似文献
19.
A. B. Manenkov 《Optical and Quantum Electronics》2013,45(6):529-541
The problem of guided mode reflection from an abruptly terminated planar metamaterial waveguide is studied by the variational technique. The theory is illustrated by examples of abruptly terminated three-layer waveguides with step permittivity and permeability profiles. Differences in the scattering characteristics for systems with metamaterials and usual media are discussed. 相似文献
20.
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