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Electromagnetic cloaks are devices that can be used to reduce the total scattering cross section of various objects. An ideal cloak removes all scattering from an object and thus makes this object "invisible" to the electromagnetic fields…

Optics · Physics 2015-05-14 Pekka Alitalo , Henrik Kettunen , Sergei Tretyakov

Transient processes generally constitute part of energy-system cycles. If skillfully manipulated, they actually are capable of assisting systems to behave beneficially to suit designers' needs. In the present study, behaviors related to…

Computational Physics · Physics 2014-10-22 Z. J. Gao , T. M. Shih , H. Merlitz , P. J. Pagni , Z. Chen

We discuss the global scattering response of invisibility cloaks over the entire frequency spectrum, from static to very high frequencies. Based on linearity, causality and energy conservation we show that the total extinction and…

Materials Science · Physics 2013-10-25 Francesco Monticone , Andrea Alu

A new recipe for concealing objects from detection is suggested. Different with traditional cloak which deflects light around the core of the cloak to make the object inside invisible, our cloak guides the light to penetrate the core of the…

Optics · Physics 2008-08-05 Yu Luo , Jingjing Zhang , Hongsheng Chen , Bae-Ian Wu , Jin Au Kong

The experimental realization of cloaks for electromagnetic fields has been possible only in reduced schemes because of extreme material conditions required in exact cloaks. Here we analytically demonstrate that a simple arrangement of two…

Superconductivity · Physics 2011-12-14 Carles Navau , Jordi Prat-Camps , Alvaro Sanchez

This paper explores the concept of near-cloaking in the context of time-dependent heat propagation. We show that after the lapse of a certain threshold time instance, the boundary measurements for the homogeneous heat equation are close to…

Analysis of PDEs · Mathematics 2017-12-18 Richard Craster , Sebastien Guenneau , Harsha Hutridurga , Grigorios Pavliotis

The effect of electrostatic shielding for a spherical invisibility cloak with arbitrary charges inside is investigated. Our result reveals that the charge inside the cloak is a crucial factor to determine the detection. When charged bodies…

Optics · Physics 2012-11-28 Ruo-Yang Zhang , Qing Zhao , Mo-Lin Ge

Invisibility cloak capable of hiding an object can be achieved by properly manipulating electromagnetic field. Such a remarkable ability has been shown in transformation and ray optics. Alternatively, it may be realistic to create a spatial…

We analyse basic thermal cloaks designed via different geometric transforms applied to thermal cloaking. We evaluate quantitatively the efficiency of these heterogeneous anisotropic thermal cloaks through the calculation of the standard…

Materials Science · Physics 2014-09-11 David Petiteau , Sébastien Guenneau , Michel Bellieud , Myriam Zerrad , Claude Amra

It was proposed that perfect invisibility cloaks can be constructed for hiding objects from electromagnetic illumination (Pendry et al., Science 312, p. 1780). The cylindrical cloaks experimentally demonstrated (Schurig et al., Science 314,…

Optics · Physics 2008-02-25 Min Yan , Zhichao Ruan , Min Qiu

Recently, it was shown that an infinite perfectly conducting (PEC) cylinder can be nearly perfectly cloaked from normally incident electromagnetic waves using a single-layer homogeneous dielectric cladding. Here we study the electromagnetic…

Mathematical Physics · Physics 2012-11-26 Constantinos A. Valagiannopoulos , Pekka Alitalo , Sergei A. Tretyakov

In this paper we describe a numerical framework for achieving passive thermal cloaking of arbitrary shapes in both static and transient regimes. The design strategy is cast as the solution of an optimal control problem (OCP) for the heat…

Optimization and Control · Mathematics 2024-06-11 Riccardo Saporiti , Carlo Sinigaglia , Andrea Manzoni , Francesco Braghin

Invisibility cloaking not only catches the human imagination, but also promises fascinating applications in optics and photonics. By manipulating electromagnetic waves with metamaterials, researchers have been able to realize…

It has recently been shown theoretically that the time-dependent heat conduction equation is form-invariant under curvilinear coordinate transformations. Thus, in analogy to transformation optics, fictitious transformed space can be mapped…

Materials Science · Physics 2013-05-14 Robert Schittny , Muamer Kadic , Sebastien Guenneau , Martin Wegener

Transformation optics originating from the invariance of Maxwell's equations under the coordinate mapping has enabled the design and demonstration of many fascinating electromagnetic devices that were unconceivable or deemed impossible…

Materials Science · Physics 2013-11-25 Yungui Ma , Lu Lan , Wei Jiang , Fei Sun , Sailing He

Cloaking of static magnetic fields by a finite thickness type-II superconductor tube surrounded by a coaxial paramagnet shell is studied. On the basis of exact solutions to the London and Maxwell equations, it is shown that perfect cloaking…

Superconductivity · Physics 2014-02-17 S. V. Yampolskii , Y. A. Genenko

Two novel classes of spherical invisibility cloaks based on nonlinear transformation have been studied. The cloaking characteristics are presented by segmenting the nonlinear transformation based spherical cloak into concentric isotropic…

Coherent perfect absorption (CPA) is an interference process associated with the zeros of the scattering matrix that enables light-with-light interactions in linear systems, of interest for optical computing, data processing and sensing.…

The ability to control electromagnetic fields, heat currents, electric currents, and other physical phenomena by coordinate transformation methods has resulted in novel functionalities, such as cloaking, field rotations, and concentration…

Classical Physics · Physics 2017-02-07 Troy Stedman , Lilia M. Woods

We report on a new concept of cloaking objects in diffusive light regime using the paradigm of the scattering cancellation and mantle cloaking techniques. We show numerically that an object can be made completely invisible to diffusive…