arXiv subjects

R. Kheradmand

Publications and source records attributed to R. Kheradmand.

3 recordsLinked to original sources

arXiv2017

Characterization of Surface-Plasmon Polaritons at Lossy Interfaces

We characterize surface-plasmon polaritons at lossy planar interfaces between one dispersive and one nondispersive linear isotropic homogeneous media, i.e., materials or metamaterials. Specifically we solve Maxwell's equations to obtain strict bounds for the permittivity and permeability of these media such that satisfying these bounds implies surface-plasmon polaritons successfully propagate at the interface, and violation of the bounds impedes propagation, i.e., the field delocalizes from the surface into the bulk. Our characterization of surface-plasmon polaritons is valuable for checking viability of a proposed application, and, as an example, we employ our method to falsify a previous prediction that surface-plasmon propagation through a surface of a double-negative refractive index medium occurs for any permittivity and permeability; instead we show that propagation can occur only for certain medium parameters.

physics.optics↗

arXiv2016

Characterization of Hybrid Modes in Metamaterial Waveguides

In this paper, we employ the properties of metamaterials to tailor the modes of metamaterial-dielectric waveguides operating at optical frequencies. We survey the effect of fishnet metamaterial structural parameters such as the magnetic oscillation strength, magnetic resonance frequency and magnetic damping on the double-negative refractive index frequency region in metamaterials and on the hybrid-modes in slab metamaterial-dielectric waveguides. To identify the robustness of the metamaterials to fluctuations in the metamaterial structural parameters, we investigate the behavior of metamaterials under Gaussian errors on their structural parameters. Our survey enables the identification of appropriate metamaterial unit-cell structure and the permissive fluctuations on the structural parameters for further applications of metamaterials in waveguide technologies.

physics.optics↗

arXiv2015

Electromagnetic-Magnetoelectric Duality for Waveguides

We develop a theory for waveguides that respects the duality of electromagnetism, namely the symmetry of the equations arising through inclusion of magnetic monopoles in addition to including electrons (electric monopoles). The term magnetoelectric potential is sometimes used to signify the magnetic-monopole induced dual to the usual electromagnetic potential. To this end, we introduce a general theory for describing modes and characteristics of waveguides based on mixed-monopole materials, with both electric and magnetic responses. Our theory accommodates exotic media such as double-negative, near-zero and zero-index materials, and we demonstrate that our general theory exhibits the electromagnetic duality that would arise if we were to incorporate magnetic monopoles into the media. We consider linear, homogeneous, isotropic waveguide materials with slab and cylindrical geometries. To ensure manifest electromagnetic duality, we construct generic electromagnetic susceptibilities that are dual in both electric charges and magnetic monopoles using a generalized Drude-Lorentz model that manifests this duality. Our model reduces to standard cases in appropriate limits. We consider metamaterials and metamaterial waveguides, as well as metal guides, as examples of waveguides constructed of mixed-monopole materials, to show the generality of our waveguide theory. In particular, we show that, in slab and cylindrical waveguides, exchanging electric and magnetic material properties leads to the exchange of transverse magnetic and transverse electric modes and dispersion equations, which suggests a good test of the potential duality of waveguides. This theory has the capability to predict waveguide behavior under an exchange of electromagnetic parameters from the dual waveguide.

physics.optics↗