In this letter we show that equivalent circuits offer a qualitative and even quantitative simple explanation for the behavior of various types of left-handed (or negative index) meta-materials. This allows us to optimize design features and parameters, while avoiding trial and error simulations or fabrications. In particular we apply this unifying circuit approach in accounting for the features and in optimizing the structure employing parallel metallic bars on the two sides of a dielectric film.
Using an extended plane-wave-based transfer-matrix method, the photonic band structures and the corresponding transmission spectrum of a two-dimensional left-handed photonic crystal are calculated. Comparisons between the periodic structure with a single left-handed cylindric rod are made, and many interesting similarities are found. It is shown that, due to the localized surface polaritons presented by an isolated left-handed rod, there exist many exciting physical phenomena in high-dimensional left-handed photonic crystals. As direct results of coupling of the localized surface polaritons of…
The spectrum of guided modes of linear chain of dielectric and left-handed cylinders is analyzed. The structure of eigenfrequences is much more richer if cylinders are made from the left-handed material with both permittivity and permeability negative. he number of guided modes is much larger, and their interaction with incident electromagnetic wave is much stronger. For some value of the wave vector, no guided modes were found. We discuss how these specific properties of guided modes correspond to folded bands, observed recently in photonic structureswith left-handed components.
We study the propagation of surface polaritons in a left-handed curved slab, i.e. a curved slab made of a negative-refractive-index material. We consider the effects of the slab curvature on their dispersion relations and attenuations. We show more particularly that surface polaritons with a "left-handed behavior" (i.e. with opposite group and phase velocities) propagate without any attenuation.
We have investigated the transmission and reflection properties of structures incorporating left-handed materials with graded index of refraction. We present an exact analytical solution to Helmholtz' equation for a graded index profile changing according to a hyperbolic tangent function along the propagation direction. We derive expressions for the field intensity along the graded index structure, and we show excellent agreement between the analytical solution and the corresponding results obtained by accurate numerical simulations. Our model straightforwardly allows for arbitrary spectral di…
We propose the use of a left-handed material in an optical waveguide structure to reduce its thickness well below the wavelength of light. We demonstrate that a layer of left-handed material, added to the cladding of a planar waveguide rather than to its core, allows for good light confinement in a subwavelength thin waveguide. We attribute the observed behavior to the change in phase evolution of electromagnetic waves in the guide. This technique can be used for the miniaturization of photonic integrated circuits.
In this paper, the microwave pulse propagation transferred through a left-handed transmission line using Complementary Omega-Like Structures (COLS) loaded was studied. There was a stop band in transmission from 5.6GHz to 6.1GHz, and the anomalous dispersion was causes in this band. Negative group velocity corresponds to the case in which the peak of the pulse exited before the peak of the incident pulse had entered the sample. The negative group velocity reached (-0.27c~-1.85c).
We analyze how chirality can generate pulling optical forces and left-handed torques by cross-coupling linear-to-angular momenta between the light field and the chiral object. In the dipolar regime, we reveal that such effects can emerge from a competition between non-chiral and chiral contributions to dissipative optical forces and torques, a competition balanced by the strength of chirality of the object. We extend the analysis to large chiral spheres where the interplay between chirality and multipolar resonances can give rise to a break of symmetry that flips the signs of both optical forc…
We provide rigorous numerical calculations (using the rigorous coupled-wave analysis) of transmission spectra of various metallic and metamaterial one-dimensional gratings and identify plasmonic resonances responsible for enhanced transmission. We argue that the most important mechanism which influences the resonant transmission is the coupling of incident electromagnetic wave with two plasmonic waves: lengthwise plasmons, which propagates along the grating, and crosswise plasmons excited in air gaps.
We show that the periodic array of left-handed cylinders possesses a rich spectrum of guided modes when the negative permeability of cylinders equals exactly to minus value of permeability of embedding media. These resonances strongly influences propagation of electromagnetic waves through photonic structures made from left-handed materials. A series of Fano resonances excited by incident wave destroys the band frequency spectrum of square array of left-handed cylinders and increases considerably the absorption of transmitted waves.
We study resonant tunneling through a layered medium with a negative index medium (NIM) slab as a constituent layer. We demonstrate large delays in transmission mediated by the surface and the guided modes of the structure with low losses. We show how important it is to include NIM dispersion for correct assessment of the nature and magnitude of the delay. We also point out the role of NIM absorption for the feasibility of such compact delay devices.
We perform a theoretical investigation on the Goos-Hächen (GH) shift in one-dimensional photonic crystals (1DPCs) containing left-handed metamaterials (LHMs). We find an unusal effect of the GH shift near the photonic band-crossing structure, which is located at the condition, $% -k_{z}^{(A)}d_{A}=k_{z}^{(B)}d_{B}=mπ$ $(m=1,2,3...)$, under the inclined incident angle, here A denotes the LHM layer and B denotes the dielectric layer. Above the frequency of the band-crossing point (BCP), the GH shift changes from negative to positive as the incident angle increases, while the GH shift changes rev…
It is shown that artificial magnetism with relatively large frequency bandwidth can be obtained from periodic arrangements of dielectric rings. Combined with dielectric rods, dielectric rings can provide 3D isotropic left-handed metamaterials being an advantageous alternative to metallic split ring resonators and/or metallic wires when un-detectability by low frequency external magnetic fields is desired. Furthermore it is shown that dielectric rings can be also combined with natural plasma-like media to obtain a left-handed metamaterial.
A bulk left-handed metamaterial with fishnet structure is investigated to show the optical loss compensation via surface plasmon amplification, with the assistance of a Gaussian gain in PbS quantum dots. The optical resonance enhancement around 200 THz is confirmed by the retrieval method. By exploring the dependence of propagation loss on the gain coefficient and metamaterial thickness, we verify numerically that the left-handed response can endure a large propagation thickness with ultralow and stable loss under a certain gain coefficient.
We study a ring cavity filled with a slab of a right-handed material and a slab of a left-handed material. Both layers are assumed to be nonlinear Kerr media. First, we derive a model for the propagation of light in a left-handed material. By constructing a mean-field model, we show that the sign of diffraction can be made either positive or negative in this resonator, depending on the thicknesses of the layers. Subsequently, we demonstrate that the dynamical behavior of the modulation instability is strongly affected by the sign of the diffraction coefficient. Finally, we study the dissipativ…
We study the propagation of quasi-discrete microwave solitons in a nonlinear left-handed coplanar waveguide coupled with split ring resonators. By considering the relevant transmission line analogue, we derive a nonlinear lattice model which is studied analytically by means of a quasi-discrete approximation. We derive a nonlinear Schr{ö}dinger equation, and find that the system supports bright envelope soliton solutions in a relatively wide subinterval of the left-handed frequency band. We perform systematic numerical simulations, in the framework of the nonlinear lattice model, to study the p…
By studying the rotations of the polarization of light propagating in right and left handed films, with emphasis on the transmission (Faraday effect) and reflec- tions (Kerr effect) of light and through the use of complex values representing the rotations, it can be shown that the real portions of the complex angle of Faraday and Kerr rotations are odd functions with respect to the refractive index n and that the respective imaginary portions of the angles are an even function of n. Multiple reflections within the medium lead to the maximums of the real portions of Faraday and Kerr effects to …
Left-handed materials usually are realized in artificial subwavelength structures. Here we show that some anisotropic superconductors, such as $\mathrm{Bi_2Sr_2CaCu_2O_{8+δ}}$, $\mathrm{YBa_2Cu_xO_y}$ and $\mathrm{La_{2-x}Sr_xCuO_4}$, are intrinsic left-handed materials. The condition is that the plasma frequency in the $c$ axis, $ω_c$, and in the $ab$ plane, $ω_{ab}$, and the operating frequency, $ω$, satisfy $ω_c<ω<ω_{ab}$. In addition $ω$ should be smaller than the superconducting energy gap to sustain superconductivity. We study the reflection and transmission of electromagnetic waves, and…
