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An elastic cloak hides a hole or an inhomogeneity from elastic fields. In this paper, a formulation of the optimal design of elastic cloaks based on the adjoint state method, in which the balance of linear momentum is enforced as a…

Computational Engineering, Finance, and Science · Computer Science 2023-05-31 Fabio Sozio , Mostafa Faghih Shojaei , Arash Yavari

We develop an optimization framework for the design of acoustic cloaks, with the aim of overcoming the limitations of usual transformation-based cloaks in terms of microstructure complexity and shape arbitrarity of the obstacle. This is…

Optimization and Control · Mathematics 2022-02-16 Sebastiano Cominelli , Davide Enrico Quadrelli , Carlo Sinigaglia , Francesco Braghin

At any energy E > 0, we construct a sequence of bounded potentials $V^E_{n}, n\in\N$, supported in an annular region $B_{out}\setminus B_{inn}$ in three-space, which act as approximate cloaks for solutions of Schr\"odinger's equation: For…

Mathematical Physics · Physics 2008-12-10 Allan Greenleaf , Yaroslav Kurylev , Matti Lassas , Gunther Uhlmann

We study the approximate cloaking via transformation optics for electromagnetic waves in the time harmonic regime in which the cloaking device {\it only} consists of a layer constructed by the mapping technique. Due to the fact that…

Analysis of PDEs · Mathematics 2018-11-02 Hoai-Minh Nguyen , Loc Tran

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

Electromagnetic invisible devices usually designed by transformation optics are rather complicated in material parameters and not suitable for general applications. Recently a topology optimized cloak based on level-set method was proposed…

Optics · Physics 2015-06-17 Lu Lan , Fei Sun , Yichao Liu , C. K. Ong , Yungui Ma

Nonmagnetic cloak offers a feasible way to achieve invisibility at optical frequencies using materials with only electric responses. In this letter, we suggest an approximation of the ideal nonmagnetic cloak and quantitatively study its…

Optics · Physics 2010-06-01 Jingjing Zhang , Yu Luo , Niels Asger Mortensen

This paper is concerned with the invisibility cloaking in electromagnetic wave scattering from a new perspective. We are especially interested in achieving the invisibility cloaking by completely regular and isotropic mediums. Our study is…

Mathematical Physics · Physics 2017-01-20 Jingzhi Li , Xiaofei Li , Hongyu Liu , Yuliang Wang

An analytical method of electromagnetic wave interactions with a general radially anisotropic cloak is established. It is able to deal with arbitrary parameters ($\epsilon_r(r)$, $\mu_r(r)$, $\epsilon_t(r)$ and $\mu_t(r)$) of a radially…

Optics · Physics 2009-10-02 Cheng-Wei Qiu , Andrey Novitsky , Hua Ma , Shaobo Qu

We theoretically and numerically demonstrate that hydrodynamic cloaking can be achieved by simply adjusting the geometric depth of a region surrounding an object in microscale flow, rendering the external flow field undisturbed. Using the…

Fluid Dynamics · Physics 2025-06-23 Hongyu Liu , Zhi-Qiang Miao , Guang-Hui Zheng

We start by a review of the chronology of mathematical results on the Dirichlet-to-Neumann map which paved the way towards the physics of transformational acoustics. We then rederive the expression for the (anisotropic) density and bulk…

Mathematical Physics · Physics 2011-07-27 Guillaume Dupont , Mohamed Farhat , Andre Diatta , Sebastien Guenneau , Stefan Enoch

Artificially structured metamaterials have enabled unprecedented flexibility in manipulating electromagnetic waves and producing new functionalities, including the cloak of invisibility based on coordinate transformation. Here we present…

Transformation optics constructions have allowed the design of cloaking devices that steer electromagnetic, acoustic and quantum waves around a region without penetrating it, so that this region is hidden from external observations. The…

Analysis of PDEs · Mathematics 2011-01-04 Matti Lassas , Ting Zhou

Despite much interest and progress in optical spatial cloaking, a three-dimensional (3D), transmitting, continuously multidirectional cloak in the visible regime has not yet been demonstrated. Here we experimentally demonstrate such a cloak…

Optics · Physics 2015-03-10 Joseph S. Choi , John C. Howell

This article deals with the numerical approximation of effective coefficients in stochastic homogenization of discrete linear elliptic equations. The originality of this work is the use of a well-known abstract spectral representation…

Probability · Mathematics 2010-08-20 Antoine Gloria , Jean-Christophe Mourrat

We complete the `paraxial' (small-angle) ray optics cloaking formalism presented previously [Choi and Howell, Opt. Express 22, 29465 (2014)], by extending it to the full-field of light. Omnidirectionality is then the only relaxed parameter…

Optics · Physics 2015-06-11 Joseph S. Choi , John C. Howell

The aim of this paper is to extend the method of improving cloaking structures in the conductivity to scattering problems. We construct very effective near-cloaking structures for the scattering problem at a fixed frequency. These new…

Analysis of PDEs · Mathematics 2015-05-30 Habib Ammari , Hyeonbae Kang , Hyundae Lee , Mikyoung Lim

The aim of this work is to derive sharp quantitative estimates of the qualitative convergence results developed in [28] for regularized full- and partial-cloaks via the transformation-optics approach. Let $\Gamma_0$ be a compact set in…

Analysis of PDEs · Mathematics 2015-08-20 Youjun Deng , Hongyu Liu , Gunther Uhlmann

In this paper we study point transformed electromagnetic invisibility cloaks in transformation media that are obtained by transformation from general anisotropic media. We assume that there are several cloaks located in different points in…

Optics · Physics 2009-11-13 Ricardo Weder

An acoustic cloak envelopes an object so that sound incident from all directions passes through and around the cloak as though the object were not present. A theory of acoustic cloaking is developed using the transformation or…

Materials Science · Physics 2008-07-13 Andrew N. Norris