Transformation optics

About: Transformation optics is a research topic. Over the lifetime, 2687 publications have been published within this topic receiving 102378 citations.

Retrieval of material parameters for uniaxial metamaterials

Abstract: We present a general method for retrieving the effective tensorial permittivity of uniaxially anisotropic metamaterials. By relaxing the usually imposed constraint of assuming nonmagnetic metal/dielectric metamaterials, we also retrieve the effective permeability tensor and show that multilayer hyperbolic metamaterials exhibit a strong and broadband diamagnetic response in the visible regime. The method provides the means for designing magnetically anisotropic metamaterials for studying magnetic topological transitions in the visible regime. We obtain orientation-independent effective material parameters, which are distinguishable from mere wave parameters. We analytically validate this method for Ag/SiO_2 planar metamaterials with a varying number of layers and filling fractions and compare to the results from effective medium theory and Bloch theory.

Equivalent circuit analysis of metamaterial strain-dependent effective medium parameters

Abstract: In this paper, we analytically describe the strain-dependent effective medium properties for a metamaterial electric-LC (ELC) resonator, commonly used in metamaterial designs to provide a tailored electric response to electromagnetic waves. Combining an equivalent circuit model of the ELC resonator with existing analytic expressions for the capacitive and inductive regions comprising the structure, we obtain strain-dependent permittivity and permeability curves for the metamaterial. The derived expressions account for the effects of spatial dispersion and losses.

Observation of slow-light in a metamaterials waveguide at microwave frequencies

Abstract: We report an experimental observation of slow-light in the GHz microwave regime utilizing the mechanism of the degeneracy of forward and backward waves in a planar waveguide consisting of a dielectric core cladded by single-negative metamaterial. The metamaterial cladding consists of periodic arrays of metallic split-ring resonators, exhibiting an effective negative permeability. Group delay dispersions obtained from pulsed measurements are in complete agreement with theoretical predictions.

Polarization controller based on embedded optical transformation.

Abstract: A universal 2D transformation formula for embedded transformation optics is suggested. Linear and nonlinear transformation results using the suggested formula under different conditions reveal several interesting phenomena and potential applications, and designs for various polarization controllers can be achieved based on this idea. For example, an incident Gaussian beam can be transformed into a typical spherical wave, and a “cloak” based on a polarization splitter is proposed for the first time.

Resonance properties of optical all-dielectric metamaterials using two-dimensional multipole expansion

Abstract: We examine the electromagnetic response of metamaterial unit elements consisting of dielectric rods embedded in a nonmagnetic background medium. We establish a theoretical framework in which the response is described through the electric and magnetic multipole moments that are simultaneously generated via the polarization currents that are excited upon the incidence of plane waves. The corresponding dipole and quadrupole polarizabilities are then calculated as a function of the Mie scattering coefficients, and their resonances are mapped for the case of dielectric cylindrical rods as a function of the geometry and the material parameters used. The results provide critical insight into the anisotropic response of two-dimensional rod-type metamaterials and can be used as a unified methodology in the calculation of exotic effective electromagnetic parameters involved in phenomena such as optical magnetism.