Negative refraction and partial focusing with a crossed wire mesh: Physical insights and experimental verification

Morgado, Tiago A.; Marcos, João; Maslovski, Stanislav I.; Silveirinha, Mário G.

doi:10.1063/1.4734510

Cited by 17 publications

(11 citation statements)

References 16 publications

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“…At microwave frequencies wire media as an artificial material has been known for a long time [1], [2], and it has gained attention in the last two decades in metamaterials research ranging from microwaves to optics in relation to observed anomalous wave phenomena such as negative refraction [3]- [9], canalization, transport, and magnification of the near field to distances of several wavelengths [10]- [14], subwavelength imaging of the near field [15]- [22], and radiative heat transfer [23]- [25]. A broad range of applications of wire-media metamaterials at terahertz (THz) and optical frequencies is given in [26].…”

Section: Introductionmentioning

confidence: 99%

An Equivalent ABCD-Matrix Formalism for Non-Local Wire Media With Arbitrary Terminations

Yakovlev

Silveirinha

Hanson

et al. 2020

IEEE Trans. Antennas Propagat.

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A simple analytical model based on the transmission-matrix approach is proposed for equivalent wire-medium (WM) interfaces. The obtained ABCD matrices for equivalent interfaces capture the non-local effects due to the evanescent transverse magnetic (TM) WM mode and in part due to the propagating transverse electromagnetic (TEM) WM mode. This enables one to characterize the overall response of bounded WM structures by cascading the ABCD matrices of equivalent WM interfaces and WM slabs as transmission lines supporting only the propagating TEM WM mode, resulting in a simple circuit-model formalism for bounded WM structures with arbitrary terminations, including the open-end, patch/slot arrays, and thin metal/2D material, among others. The individual ABCD matrices for equivalent WM interfaces apparently violate the conservation of energy and reciprocity, and therefore, the equivalent interfaces apparently behave as nonreciprocal lossy or active systems. However, the overall response of a bounded WM structure is consistent with the lossless property maintaining the conservation of energy and reciprocity. These unusual features are explained by the fact that in the non-local WM the Poynting vector has an additional correction term which takes into account a "hidden power" due to non-local effects. Results are obtained for various numerical examples demonstrating a rapid and efficient solution for bounded WM structures, including the case of geometrically complex multilayer configurations with arbitrary terminations, subject to the condition that WM interfaces are decoupled by the evanescent TM WM mode below the plasma frequency. Index Terms-Wire medium, homogenization theory, spatial dispersion (SD), additional boundary condition (ABC), metamaterials, ABCD matrix.

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Section: Introductionmentioning

confidence: 99%

An Equivalent ABCD-Matrix Formalism for Non-Local Wire Media With Arbitrary Terminations

Yakovlev

Silveirinha

Hanson

et al. 2020

IEEE Trans. Antennas Propagat.

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“…in [18]). Electromagnetic properties of these structures have a number of common features with hyperbolic materials (enhancement of radiation from small sources, negative refraction at interfaces [19,20], etc), although wave-guiding media are formed by ordinary metals and dielectrics, and, moreover, due to their strongly spatially dispersive nature, cannot be described by a local permittivity tensor. Realizations of wave-guiding media do not necessarily require exotic materials with negative and positive permittivities.…”

Section: Introductionmentioning

confidence: 99%

“…It is found that a simple periodical array of PEC strips to some extent behaves similarly to hyperbolic materials and can offer a variety of means to control electromagnetic waves with flexibility and robustness. In contrast to earlier studies of tilted wire-medium slabs [19,20], which are based on corresponding homogenized models, we consider the actual TEM waveguides formed between the PEC strips. where the used Cartesian coordinate system ( )…”

Section: Introductionmentioning

confidence: 99%

Emulating hyperbolic-media properties with conventional structures

Valagiannopoulos¹,

Tretyakov²

2014

New J. Phys.

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Hyperbolic media (media with hyperbolically-shaped dispersion surfaces) possess interesting properties which have inspired numerous application concepts. In this study, we try to identify conventional materials which resemble the behavior of hyperbolic media. We start from biaxial concepts and conclude that a necessary condition for that purpose is the high permittivity contrast between the two axes. Since components with substantial permittivity magnitude are behaving like PEC boundaries, we consider an electrically dense mesh of tilted PEC strips formulating numerous parallel TEM waveguides as a possible substitute to hyperbolic structures. Indeed, this wave-guiding medium is found to exhibit hyperbolic properties via semi-analytical approximations which have been verified by full-wave simulations. The design flexibility provided by the increased independence between the formulated consecutive waveguides can be exploited in a variety of different objectives when controlling electromagnetic fields.

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“…Such engineered structures have yielded an 'effective' electromagnetic response that is normally not encountered in nature. Aside from enabling these new frontiers and interesting scientific properties such as a negative index of refraction, 10,11 negative refraction, 12 indefinite media 13 or nearfield imaging, 11,14 MTMs have shown to be beneficial for various existing applications. For instance, MTMs show superior performance over prior techniques for absorption, wave guidance and narrowband emission of light for solar and/or thermal photovoltaic cell applications.…”

Section: Introductionmentioning

confidence: 99%

Light concentration using hetero-junctions of anisotropic low permittivity metamaterials

Memarian

Eleftheriades

2013

Light Sci Appl

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Focusing incident power into an area of high concentration is of significant interest for various applications. In optics, this has been traditionally achieved with lenses where a higher curvature and lens permittivity typically result in shorter focal distances (low f/D). In this work, we present designs and techniques for collecting, refracting and guiding incident light into an area of high power concentration (a hot spot) at extremely short distances. Specifically, a flat low-profile focusing mechanism is presented using a hetero-junction of anisotropic metamaterials (MTMs). The hetero-junction is formed from two cleaved finite slabs of low (near zero) permittivity anisotropic MTMs with rotated optical axes. The MTMs have near zero longitudinal permittivity while matched in the transverse direction. Such MTMs are shown to provide a unique ability to bend the transverse magnetic or p-polarized light away from the normal and along the interface, contrary to conventional dielectrics, and with minimal reflections; hence allowing for a low profile design. Realizations in the optical regime are presented using periodic bilayers of metal and dielectric. The proposed hetero-junction focusing device concentrates the normally incident plane wave and/or beam into a corresponding focal region similar to a lens via multiple refractions. The hetero-junction is capable of creating a hot spot very close to the device, much closer than dielectric lenses and it significantly outperforms the size requirements of thick high curvature lenses with low f/D ratios. The proposed designs can find applications in various scenarios including solar and thermo photovoltaics, photodetectors, concentrated photovoltaics, non-imaging optics, micro-and nano-Fresnel lenses.

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Negative refraction and partial focusing with a crossed wire mesh: Physical insights and experimental verification

Cited by 17 publications

References 16 publications

An Equivalent ABCD-Matrix Formalism for Non-Local Wire Media With Arbitrary Terminations

An Equivalent ABCD-Matrix Formalism for Non-Local Wire Media With Arbitrary Terminations

Emulating hyperbolic-media properties with conventional structures

Light concentration using hetero-junctions of anisotropic low permittivity metamaterials

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