Topic
Transformation optics
About: Transformation optics is a research topic. Over the lifetime, 2687 publications have been published within this topic receiving 102378 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: This work takes a gradual approach to homogenization, asking not whether, but to what extent a composite metamaterial approaches the sought after effective medium.
Abstract: We present a two-step homogenization method for composite metamaterials. First, each layer of wires or resonators is homogenized as a slab with negative permittivity or permeability, respectively. Second, the single negative stack which results is homogenized to form the effective medium. Comparing the predictions of the first and second step can serve as a gauge of the homogeneity of the composite. We thus take a gradual approach to homogenization, asking not whether, but to what extent a composite metamaterial approaches the sought after effective medium. Our two-step approach can also capture phenomena which otherwise may be wrongly attributed to effective medium behavior. We illustrate by qualitatively reproducing and reinterpreting a set of experimental data from the literature.
54 citations
TL;DR: The theory and implementation of this MTS transformation allows for a deformation of the SW wavefront which addresses the local wavevector along not-rectilinear paths and can be analysed in the framework of transformation optics.
Abstract: Metasurfaces (MTSs) constitute a class of thin metamaterials used for controlling plane waves and surface waves (SWs). At microwave frequencies, they are constituted by a metallic texture with elements of sub-wavelength size printed on thin grounded dielectric substrates. These structures support the propagation of SWs. By averaging the tangential fields, the MTSs can be characterized through homogenized isotropic or anisotropic boundary conditions, which can be described through a homogeneous equivalent impedance. This impedance can be spatially modulated by locally changing the size/orientation of the texture elements. This allows for a deformation of the SW wavefront which addresses the local wavevector along not-rectilinear paths. The effect of the MTS modulation can be analysed in the framework of transformation optics. This article reviews theory and implementation of this MTS transformation and shows some examples at microwave frequencies.
54 citations
TL;DR: The general full-wave analysis shows that the obtained quasistatic conditions are useful in designing the electromagnetically transparent materials.
Abstract: With the help of the "neutral inclusion" concept, the conditions of electromagnetic wave transparency for multilayered spheres, coated spheroids, and general particulate composites are analytically derived in the quasistatic case. The basic idea is to make the effective material property of a composite region equal to that of the surrounding medium. The general full-wave analysis shows that the obtained quasistatic conditions are useful in designing the electromagnetically transparent materials.
54 citations
TL;DR: Numerical simulations verify that the metamaterial immersion lenses possess exceptionally large effective numerical apertures thus can achieve deep subwavelength resolution focusing and discuss the importance of the losses in modulating the optical transfer function and thus in enhancing the performance of the meetamaterial immersed lenses.
Abstract: We propose and demonstrate metamaterial immersion lenses by shaping plasmonic metamaterials. The convex and concave shapes for the elliptically and hyperbolically dispersive metamaterials are designed using phase compensation method. Numerical simulations verify that the metamaterial immersion lenses possess exceptionally large effective numerical apertures thus can achieve deep subwavelength resolution focusing. We also discuss the importance of the losses in modulating the optical transfer function and thus in enhancing the performance of the metamaterial immersion lenses.
54 citations
TL;DR: In this article, an approach for retrieving effective parameters of metamaterials based on the Bloch-mode analysis of quasiperiodic composite structures is proposed. But the method is not suitable for the case of single-mode propagation.
Abstract: We introduce an approach for retrieving effective parameters of metamaterials based on the Bloch-mode analysis of quasiperiodic composite structures. We demonstrate that, in the case of single-mode propagation, a complex effective refractive index can be assigned to the structure, being restored by our method with a high accuracy. We employ both surface and volume averaging of the electromagnetic fields of the dominating (fundamental) Bloch modes to determine the Bloch and wave impedances, respectively. We discuss how this method works for several characteristic examples, and demonstrate that this approach can be useful for retrieval of both material and wave effective parameters of a broad range of metamaterials.
54 citations