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Transformation optics

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


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Journal ArticleDOI
TL;DR: The geometric optics principles are used to develop a unidirectional transmission cloak for hiding objects with dimensions substantially exceeding the incident radiation wavelengths, and it demonstrates efficient multiband performance confirmed by full-wave simulations.
Abstract: The geometric optics principles are used to develop a unidirectional transmission cloak for hiding objects with dimensions substantially exceeding the incident radiation wavelengths. Invisibility of both the object and the cloak is achieved without metamaterials, so that significant widths of the cloaking bands are provided. For the preservation of wave phases, the λ-multiple delays of waves passing through the cloak are realized. Suppression of reflection losses is achieved by using half-λ multiple thicknesses of optical elements. Due to periodicity of phase delay and reflection suppression conditions, the cloak demonstrates efficient multiband performance confirmed by full-wave simulations.

12 citations

Journal ArticleDOI
TL;DR: In this article, the radial component of the permittivity or permeability tensor tends to zero and the coherent omnidirectional radiations will occur when sources are within the fan-shaped metamaterial backed with perfect magnetic conductors, which leads to spatial power combination in finite areas.
Abstract: We show that the radially anisotropic zero-index metamaterials can be used to realize spatial power combination within fan-shaped regions. When the radial component of the permittivity or permeability tensor tends to zero, the coherent omnidirectional radiations will occur when sources are within the fan-shaped metamaterial backed with perfect magnetic conductors (PMCs), which leads to spatial power combination in finite areas. As the included angle of the PMC corner reflector decreases, the powers from internal sources can still be efficiently combined, which has potential applications in radio frequency engineering.

12 citations

Journal ArticleDOI
TL;DR: The theoretical analysis of this class of multilayered composite active acoustic metamaterials (CAAMM) is presented and the theoretical predictions are determined for a cascading array of fluid cavities coupled to flexible piezoelectric active boundaries forming the meetamaterial domain with programmable dynamic density.
Abstract: Considerable interest has been devoted to the development of various classes of acoustic metamaterials that can control the propagation of acoustical wave energy throughout fluid domains. However, all the currently exerted efforts are focused on studying passive metamaterials with fixed material properties. In this paper, the emphasis is placed on the development of a class of composite one-dimensional acoustic metamaterials with effective densities that are programmed to adapt to any prescribed pattern along the metamaterial. The proposed acoustic metamaterial is composed of a periodic arrangement of cell structures, in which each cell consists of a circular sector cavity bounded by actively controlled flexible panels to provide the capability for manipulating the overall effective dynamic density. The theoretical analysis of this class of multilayered composite active acoustic metamaterials (CAAMM) is presented and the theoretical predictions are determined for a cascading array of fluid cavities coupled to flexible piezoelectric active boundaries forming the metamaterial domain with programmable dynamic density. The stiffness of the piezoelectric boundaries is electrically manipulated to control the overall density of the individual cells utilizing the strong coupling with the fluid domain and using direct acoustic pressure feedback. The interaction between the neighboring cells of the composite metamaterial is modeled using a lumped-parameter approach. Numerical examples are presented to demonstrate the performance characteristics of the proposed CAAMM and its potential for generating prescribed spatial and spectral patterns of density variation.

12 citations

01 Jan 2011
TL;DR: In this article, the theory of transformation optics provides people with a perfect tool to make us make use of metamaterials, and the first experimental realization of double negative media.
Abstract: Research on metamaterials has been growing ever since the first experimental realization of double negative media. The theory of transformation optics provides people with a perfect tool to make us ...

12 citations

Journal ArticleDOI
TL;DR: In this paper, a passive DC magnetic concentrator is designed with transformation optics and realized by meta-materials, which can greatly enhance the magnetic field in a free space region and can be used for improving the sensitivity of magnetic sensors and increasing the efficiency of wireless energy transmission.
Abstract: A passive DC magnetic concentrator is designed with transformation optics (TO) and realized by meta-materials. The passive DC magnetic concentrator based on space compression transformation can greatly enhance the magnetic field in a free space region and can be used for e.g., improving the sensitivity of magnetic sensors and increasing the efficiency of wireless energy transmission. The magnetic property of the medium obtained by TO is extremely anisotropic. To solve this, we use magnetic metamaterials made of alternated high-permeability ferromagnetic (HPF) materials and high-temperature superconductor (HTS) materials. We optimize our structure by conducting simulations using the finite element method (FEM) and experimentally demonstrate a strong, 4.74-time enhancement of the DC magnetic field by our meta-material magnetic concentrator. We also demonstrate that a simplified structure with only HPF materials working at room temperature can still gives 3.84-time enhancement of the DC magnetic field. The experimental results are in good agreement with the numerical simulations based on FEM.

12 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202324
202269
202147
202070
2019100
201890