共查询到20条相似文献,搜索用时 15 毫秒
1.
E. Demirel A. C. Basaran B. Aktas 《The European Physical Journal B - Condensed Matter and Complex Systems》2009,69(2):173-180
In this paper, we present theoretical and experimental results for the indication of negative refraction in ferromagnetic
metallic wire lattice. We have studied microwave transmission through a two dimensional wire lattice made of ferromagnetic
metallic wires under the applied static magnetic field. We have found that, the microwave transmission were significantly
changed at ferromagnetic resonance frequency region. Thus the magnetic permeability can be tuned by external dc magnetic field.
Since the dielectric permittivity of metallic wire lattice is negative and can take a value close to unity then the crystal
exhibits negative index of refraction at microwave region under the external magnetic field. 相似文献
2.
E.V. Ponizovskaya A.M. Bratkovsky 《Applied Physics A: Materials Science & Processing》2007,87(2):175-179
Arrays of metallic nanoparticles support individual and collective plasmonic excitations that contribute to unusual phenomena
like surface-enhanced Raman scattering, anomalous transparency, negative index, and subwavelength resolution in various metamaterials.
We examined the electromagnetic response of dual Kron’s lattice and films containing up to three monolayers of metallic nanospheres.
It appears that open cubic Kron’s lattice exhibits ‘soft’ electromagnetic response but no negative index behavior. The close-packed
arrays behave similarly: there are plasmon resonances and very high transmission at certain wavelengths that are much larger
than the separation between the particles, and a ‘soft’ magnetic response, with small but positive effective index of refraction.
It would be interesting to check these predictions experimentally.
PACS 78.20.Ci; 42.30.Wb; 73.20.Mf; 42.25.Bs 相似文献
3.
Z. Tang H. Zhang R. Peng Y. Ye C. Zhao S. Wen D. Fan 《Applied Physics A: Materials Science & Processing》2007,87(2):223-225
As distinct from coated photonic crystals, in this paper we propose a novel one that is made of dielectric tubes arranged
in a close-packet square lattice. Without metallic cores, this structure is low-loss and convenient to fabricate. A left-handed
frequency region is found in the second band by dispersion characteristic analysis. Without inactive modes for the transverse
electric mode, negative refraction and subwavelength imaging are demonstrated by the finite-difference time-domain simulations
with two symmetrical interfaces, i.e. ΓX and ΓM.
PACS 78.20.Ci; 41.20.JB; 42.70.Qs; 41.85.Ct; 42.30.Va 相似文献
4.
5.
We systematically investigate the band structures, equifrequency surfaces, and the intensity distributions of Poynting vector in two-dimensional Si/SiO2 all-solid photonic crystals with different lattice types. It is found that all-angle negative refraction with effective refractive index of nearly ? 1 and far-field imaging effects can be achieved from all-solid photonic crystals. And more important thing is that, the all-solid photonic crystals can realize all-angle negative refraction at lower frequencies and provide far-field images with higher quality compared with normal air–dielectric photonic crystals. Such improved performance provides an alternative approach to realize all-angle negative refraction in super-lens and super-prisms applications. 相似文献
6.
Christian Imhof Remigius Zengerle 《Applied Physics A: Materials Science & Processing》2009,94(1):45-49
We report on microwave experiments with a metamaterial composed of pairs of metallic crosses. The transmission properties
of the structure show a left-handed transmission band at frequencies around 10.2 GHz. The validity of the negative effective
index of refraction is verified by a Snell’s law refraction experiment performed on a wedge-shaped sample of the metamaterial.
A second measurement of a similar wedge made from blank FR4 boards is done for reference. The results of the measurements
show positive refraction over the whole measured frequency band for the FR4 wedge as well as the refraction of the incident
radiation to negative angles within the designated left-handed frequency band for the metamaterial sample. 相似文献
7.
We demonstrate the negative refraction of microwaves in a metallic photonic crystal prism. The spectral response of the photonic crystal prism, which manifests both positive and negative refraction, is in complete agreement with band-structure calculations and numerical simulations. The validity of Snell's law with a negative refractive index is confirmed experimentally and theoretically. The negative refraction observed corresponds to left-handed electromagnetism that arises due to the dispersion characteristics of waves in a periodic medium. This mechanism for negative refraction is different from that in metamaterials. 相似文献
8.
Negative Refraction and Near-Field Imaging of an Elliptical-Rod Photonic Crystal Slab in the Second Band 下载免费PDF全文
Negative refraction and imaging properties of the electromagnetic wave through a two-dimensional photonic crystal (PC) slab, which consists of a square lattice of elliptical dielectric rods immersed in the air background, is studied by the plane-wave expansion method and the finite-difference time-domain method. A point source placed in the vicinity of the PC slab can form a good-quality image spot through the PC slab for the incident frequencies within the second photonic band. The calculated result also shows that negative refraction occurs in this kind of PC slab. 相似文献
9.
《Current Applied Physics》2010,10(5):1243-1248
Laser interaction of silicon film located at he top of metallic substrate is examined and energy transport in electron and lattice sub-systems are formulated using the electron kinetic theory approach. The simulations are repeated for different substrate materials, namely gold, silver, and copper. It is found that electron temperature in the silicon film rises in the vicinity of the silicon–metallic substrate interface, despite the fact that energy absorption from the irradiated filed is significantly low in the silicon film. Lattice site temperature rises rapidly in the early heating period at the interface. In addition, lattice site temperature increase is higher in the silicon film than that corresponding to the metallic substrate. 相似文献
10.
11.
Diverse imaging of point source by a two-dimensional photonic crystal slab with square lattice is studied by the finite-difference time-domain method. Given proper frequencies, there seems to be some special directions like channels guiding the light propagation inside the photonic crystal, along which some images will be created. It is suggest that except negative refraction there should be other mechanisms making point image by two dimensional photonic crystal slab. 相似文献
12.
This paper studies a small f-number metallic lens with depth-modulated slits.Slits filled with dielectric between silver plates are designed to produce desired optical phase retardations based on the particular propagation properties of surface plasmon polaritons in nanostructures.Numerical simulation of this structure is performed through the finitedifference time-domain method.Different from the conventional dielectric lens,the metallic lens can be used as a pure phase element without energy loss brought by the light refraction at curved surfaces and total internal reflection.The focusing performance is consequently improved,with larger diffraction efficiency than that of the same shaped dielectric lens. 相似文献
13.
Ling Yun Liu Dong Ping Yang Yuan Ming Zhou Ji Zhou 《Applied Physics A: Materials Science & Processing》2014,117(2):747-753
We present a detailed study on the artificial magnetism of high-permittivity dielectric spherical shell array and the negative refraction behavior of the composite consisting of dielectric spherical shells and metal wire lattice. The spherical shell array in cubic lattice arrangement can exhibit an isotropic negative magnetism when excited into magnetic dipole resonance. When the dielectric spherical shell and metal wire lattice are combined in a body-centered cubic structure, full-wave simulations show that the bulk metamaterial with this structure can exhibit a negative refraction behavior. It is shown that artificial magnetic response can originate from differently structured dielectric elements, similarly to the conventional metamaterial constituents based on metal resonance structures. 相似文献
14.
The superconducting transition temperature of the highT
c compound Y1Ba2Cu3O7−x
does not show degradation consequent upon the addition of metallic silver up to a concentration of 60 wt per cent. The X-ray
diffraction data confirm that the oxygen deficient distorted orthorhombic perovskite structure of the pure compound stays
intact as if silver does not enter the crystal lattice. SEM studies do show the presence of silver at the grain boundaries
only. Silver is found to restrict the grain growth. 相似文献
15.
利用传输矩阵方法,模拟研究了FC(N)准晶链排列的多层介质膜中存在不同缺陷情形时,光在其中传播的透射规律.结果表明,当Fibonacci准晶中存在缺陷时,引入了缺陷模,而且其缺陷模具有与自身结构相关的特点.还进一步模拟研究了存在负折射率吸收缺陷媒质时的FC(N)准晶链的透射系数,出现了共振透射率大于1的情形.同时还研究了负折射率缺陷媒质的虚部对禁带中共振透射峰大小的影响,发现并不是所有引入负折射率吸收缺陷媒质的准晶都会出现共振透射率大于1的现象. 相似文献
16.
In this paper, we study the structural, electronic and elastic properties of the ternary AgSbTe2, AgSbSe2, Pr3AlC, Ce3AlC, Ce3AlN, La3AlC and La3AlN compounds using the full-potential linearized augmented plane wave (FP-LAPW) scheme and the pseudopotential plane wave (PP-PW) scheme in the frame of generalized gradient approximation (GGA). Results are given for the lattice parameters, bulk modulus, and its pressure derivative. The calculated lattice parameters are in good agreement with experimental results. We have determined the full set of first-order elastic constants, shear modulus, Young's modulus and Poisson's ratio of these compounds. Also, we have presented the results of the band structure, densities of states, it is found that this compounds metallic behavior, and a negative gap Г→R for Pr3AlC. The analysis charge densities show that bonding is of covalent–ionic and ionic nature for AgSbSe2 and AgSbTe2 compounds. 相似文献
17.
The metallic films perforated with a periodic array of air holes show extraordinary optical transmission properties. In this paper the influence of the incident light's polarization direction and the arrays’ period on the transmission through the rectangular hole arrays immersed in a metallic film is studied by utilizing the finite-difference time-domain method. The results show that the intensities and number of the transmission peaks can be adjusted by changing the incident light's polarization direction, while the intensities can keep constant for some particular frequencies. The transmission peak's wavelength can be easily controlled by altering the lattice period parallel to the electric field for the rectangular holes. These results maybe provide reference for the design of multiple-wavelength resonance devices. 相似文献
18.
In this study, we propose guidelines to optimize the transmission and bandwidth of left handed materials (LHM) composed of two-dimensional lattice of metallic wires interleaved with double split ring resonators (SRRs). Several LHM structures are fabricated to test the proposed rules of design and operate between 7 and 14 GHz. In a first step, we show that adding extra SRR layers within each period of wire layers (i.e. interleaving the wire lattice with several SRR lattices) increases the transmittance of the material. In a second step, we demonstrate that adding extra SRR layers in a non-equidistant manner (i.e. inserting several SRR lattices shifted one another by different distances) widens the LHM frequency bandwidth. The results of experimental characterization are found to be in excellent agreement with theoretical predictions. A LHM behavior is obtained in a wide frequency band of 1 GHz around 8.2 GHz with a transmission of −1.2 dB measured at resonance. The negative refraction of the material is verified from measurements at oblique incidence. 相似文献
19.
The optical properties of colloidal silver particles formed photographically in high-resolution silver halide photographic materials have been considered. The conditions that allow one to obtain exposed and developed light-sensitive silver halide particles in the form of colloidal particles of metallic silver having the properties of localized plasmons have been described. The results of the studies of the developed silver particles in traditional photographic materials for image holography and in nanoporous silver halide photographic materials for volume holography have been presented. The perspectives of using plasmonic silver nanoparticles produced photographically have been discussed. 相似文献
20.
P. Zhang N. K. Efremidis A. Miller P. Ni Z. Chen 《Applied physics. B, Lasers and optics》2011,104(3):553-560
We report on our recent theoretical and experimental studies of three-dimensional (3D) photonic lattice structures which are
established in a bulk nonlinear crystal by employing different optical induction techniques. These 3D photonic lattices bring
about new opportunities for controlling the flow of light via coupling engineering originated from the lattice modulation
along the beam propagation direction. By fine tuning the lattice parameters, we observe a host of unusual behaviors of beam
propagation in such reconfigurable 3D lattices, including enhanced discrete diffraction, light tunneling inhibition—better
known as coherent destruction of tunneling (CDT), anomalous diffraction, negative refraction, as well as CDT-based image transmission.
In addition, we propose and demonstrate a new way of creating 3D ionic-type photonic lattices by controlled Talbot effect. 相似文献