Double-negative Metamaterial Slab Research Articles

Reconstructions of effective parameters for a metamaterial antenna via 3D-printed components

This study presents the reconstruction of effective medium parameters for a double negative metamaterial slab from the knowledge of the measured/simulated S-matrix. The structure initially has been designed to embed into a patch antenna for a radar application. To observe the medium characteristics, we locate the slab in a rectangular waveguide for various orientations. The waveguide-based retrieval method is applied to find parameters regarding the biaxial anisotropic medium. Fundamental mode is used for the excitation. Additive printing technology is employed to manufacture a rectangular waveguide and its adapters for the experiments. The metallization is achieved by coating the printed structures with conductive thin layers. Experimental setups for each orientation are simulated as well. We illustrate good agreements between simulation and measurements under the fabrication tolerances. The feasibility and applicability of the additive printing technology for the investigations of the metamaterial anisotropic/bianisotropic nature is reported.

μ-near-zero metamaterial slabs for a new concept of plasmonic sensing platforms

We demonstrate that the excitation of magnetic bulk plasmon-like resonances in μ-near-zero double-negative metamaterial slabs is suitable for the design of new sensing platforms, where light-to-plasmon coupling is reached without requiring a prism or grating coupler. This allows for excitation with light coming directly from the air and for dielectric substrates with any refractive index. In the microwave region this architecture is able to detect changes as small as 10−2 in the refractive index of the superstrate. If the metamaterial slab is backed by a metallic substrate, on the other hand, the system can be used as a light-absorber for light harvesting applications.

Simulation of Isotropic Acoustic Metamaterials

The model use to study electromagnetic metamaterials in transverse electric mode was modified to study the pressure distribution in an acoustic metamaterial in a two dimensional geometry. An electromagnetic wave of 30 GHz in transverse magnetic mode at normal incidence propagating through a two dimensional isotropic semi infinite double negative metamaterial slab of 640×830 cells embedded in free space with low loss damping frequency 108s-1 was studied by finite difference time dependent method with Yee’s algorithm with an explicit leapfrog scheme. The multiple cycle m-n-m pulses generating beams were used as sources. The simulations for refractive indices n=-1 and n=-16 at different time steps are presented. For n=-1, the sub-wavelength imaging is apparent, diverging the waves from source into two sources, one inside and the other outside the slab. The reverse propagation is much more significant for showing that the group velocity is much larger inside the metamaterial by the closely packed wave front, making the continuation of the wave pattern much more significant through the metamaterial into the normal space.

Simulation of Isotropic Acoustic Metamaterials

The model use to study electromagnetic metamaterials in transverse electric mode was modified to study the pressure distribution in an acoustic metamaterial in a two dimensional geometry. An electromagnetic wave of 30 GHz in transverse magnetic mode at normal incidence propagating through a two dimensional isotropic semi infinite double negative metamaterial slab of 640×830 cells embedded in free space with low loss damping frequency 108s-1was studied by finite difference time dependent method with Yee’s algorithm with an explicit leapfrog scheme. The multiple cyclem-n-mpulses generating beams were used as sources. The simulations for refractive indices n=-1 and n=-16 at different time steps are presented. For n=-1, the sub-wavelength imaging is apparent, diverging the waves from source into two sources, one inside and the other outside the slab. The reverse propagation is much more significant for showing that the group velocity is much larger inside the metamaterial by the closely packed wave front, making the continuation of the wave pattern much more significant through the metamaterial into the normal space.

Phase dependent coherent control of group delay in a doped metamaterial slab

A scheme is proposed for the coherent control of the group delay for a light beam traveling through a double-negative metamaterial (DNM) slab. By doping three-level atoms into the DNM slab, phase control over the transmission and reflection behaviors of the active layer is achieved. This way, tunable and simultaneous subluminal and superluminal transmission and reflection are achievable. We discuss the effect of the relative phase of the applied fields and the rate of incoherent pumping on the group delay of a probe pulse propagating through the DNM slab. It is shown that group delays of the transmitted and reflected beams are completely phase dependent. We also find that transmission of a probe field propagating through the DNM slab is actively controllable in a wide range by controlling the relative phase of the incident fields with no need to alter physical parameters of the metamaterial.

Imaging by a double negative metamaterial slab excited with an arbitrarily oriented dipole

The imaging capability of nonideal double negative metamaterial slabs excited by arbitrarily oriented electric or magnetic dipoles is investigated. A dipole oriented parallel to the interface of the slab excites transverse electric and transverse magnetic modes simultaneously, which are transmitted unequally by the slab if either the slab's relative permittivity (er) or permeability (μr) or both are perturbed from the ideal case, i.e., er=μr=−1 for a slab in vacuum. Approximations in the electrostatic limit, valid for modes with large wave numbers, fail to predict this phenomenon, and more accurate analysis of the field distribution in the vicinity of the image plane behind a nonideal slab becomes important. By expressing the fields in terms of a one‒dimensional Hankel transform in the spectral domain and using an adaptive Gauss‒Kronrod quadrature, a tool for evaluating the spatial field intensity in the vicinity of the image plane behind the slab is developed. The calculated field intensities reveal that a double negative slab does not focus in the three‒dimensional space and is only capable of two‒dimensional imaging.

Eigenvalue equation for an asymmetric left-handed metamaterial planar slab optical waveguide

In this paper, we have derived the exact eigenvalue equation by using the transmission line method for double negative metamaterial slab. The derived results have exactly matched with the existing results found in the literature. The unusual behavior of double negative metamaterial is predicted. Dispersion study, modified profile and the power con- finement factor have been predicted for the case of double negative metamaterials.

Large positive and negative generalized Goos-Hänchen shifts from a double negative metamaterial slab backed by a metal

It is found that the generalized Goos-Hanchen (GGH) shift of a light beam reflecting from a double negative metamaterial slab backed by a metal can be large positive as well as negative. We give an analytical expression for the GGH shift from which the necessary condition for the GGH shift to be positive or negative can be obtained. Numerical results validate the conclusions. A Gaussian-shaped beam was analyzed in the paraxial approximation and it was proven that there is no angular shift in this case. Finally we discuss the lossy effect of the metamaterial slab on the GGH shift.

Pulsed Gaussian beam interactions with double negative metamaterial slabs: errata

The numerical results, Figs. 16 and 18, for the double negative (DNG) metatmaterial Goos-Hänchen examples were incorrect. Corrected numerical results show closer agreement to predictions.

Pulsed and CW Gaussian beam interactions with double negative metamaterial slabs

The interactions of pulsed and continuous wave (CW) Gaussian beams with double negative (DNG) metatmaterials are considered. Subwavelength focusing of a diverging, normally incident pulsed Gaussian beam with a planar DNG slab is demonstrated. The negative angle of refraction behavior associated with the negative index of refraction exhibited by DNG metamaterials is demonstrated. The transmitted beam resulting from both 3- cycle and CW Gaussian beams that are obliquely incident on a DNG slab are shown to have this property. Gaussian beams that undergo total internal reflection from a DNG metamaterial slab are also shown to experience a negative Goos-Hänchen (lateral) shift. Several potential applications for these effects in the microwave and optical regimes are discussed.