Isotropic three-dimensional left-handed metamaterials

By Thomas Koschny, Le Zhang, Costas M. Soukoulis. 2005

138 citations recorded by the source corpus.

We investigate three-dimensional left-handed and related metamaterials based on a fully symmetric multigap single-ring split-ring resonator sSRRd design and crossing continuous wires. We demonstrate isotropic transmission properties of a SRR-only metamaterial and the corresponding left-handed material that possesses a negative effective index of refraction due to simultaneously negative effective permeability and permittivity. Minor deviations from complete isotropy are due to the finite thickness of the metamaterial. The realization of a perfect lens 1 and other applications of negative refraction require the fabrication of threedimensional, homogeneous, isotropic left-handed materials 2 sLHMd with simultaneously negative permittivity « and magnetic permeability m. So far, no such materials exist, either in nature or in the laboratory. Today’s available LHM structures, based on the periodic arrangement of split-ring resonators 3 sSRRd and continuous metallic wires, 4 are only one dimensional 5‐7 s1Dd, supporting left-handed properties only for propagation with fixed polarization in one direction, or two dimensional 8‐10 s2Dd, where propagation in two directions with fixed polarization or one direction with arbitrary polarization is possible. Earlier attempts to design at least an isotropic SRR sRef. 11d were lacking the symmetry of SRR and unit cell and required individual tuning of the parameters in the different spatial directions. In this paper, we propose a three-dimensional s3Dd isotropic LHM design that allows left-handed behavior for any direction of propagation and any polarization of the electromagnetic wave. Using numerical transfer matrix simulations, we verify the isotropic transmission properties of the proposed structures. Our data show excellent agreement with results expected for a homogeneous slab with the corresponding negative « and m. Our metamaterials are defined as a 3D periodic continuation of a single rectangular unit cell, consisting of SRRs and continuous wires. The sample is a slab of metamaterial with a finite thickness of an integral number of unit cells and infinite extent in the perpendicular direction. The two surfaces of the slab are parallel to any face of the unit cell. An incident electromagnetic plane wave with wave vector k can be characterized by two angles: the incidence angle q P f 0, p /2 d between k and the surface normal n of the sample, and the angle f P s˛p , pg between the projection of k into and some chosen edge of the unit cell inside the surface plane of the sample. The frequency of the incident wave is chosen such that the vacuum wavelength is approximately 10 times larger than the linear size of the unit cell and we expect effective medium behavior.

Subfields: Aerospace Engineering, Electronic, Optical and Magnetic Materials

View Paper: https://www.semanticscholar.org/paper/384f70023fda082317a24b4066fd964d9c70c1f9