Three-Dimensional Axisymmetric Invisibility Cloaks With Arbitrary Shapes in Layered-Medium Background

Abstract

Abstract-Three-dimensional (3D) axisymmetric invisibility cloaks with arbitrary shaped in layered-media background are presented using the transformation optics. The inner and outer boundaries of the cloaks can be non-conformal with arbitrary shapes, which considerably improve the flexibility of the cloaking applications. However, such kinds of 3D cloaks cannot be simulated using the commercial softwares due to the tremendous memory requirements and CPU time. By taking advantage of the rotationally symmetrical property, we propose an efficient finite-element method (FEM) to simulate and analyze the 3D cloaks, which can greatly reduce the CPU time and memory requirements. The method is based on the electric-field formulation, in which the transverse fields are expanded in terms of second-order edgebased vector basis functions and the azimuth components are expanded using second-order nodal-based scalar basis functions. The FEM mesh is truncated using the absorbing boundary condition. Excellent cloaking performance of the 3D cloaks in layered-media background has been verified by the proposed method.

Optical Antireflection of a Medium by Nanostructural Layers

“…The problem can thus be treated in this approach only numerically, which requires a long computation time. Similar difficulties are encountered in other methods that directly solve Maxwell's equations, such as the finite element method (FEM) [22][23][24], finite-difference time-domain (FDTD) method [25,26], small perturbation method (SPM) [27]. Moreover, taking into account the interaction between a layer of nanoparticles and the substrate adds considerable complexity to the computation process or requires a number of approximations, e.g., averaging of the refractive indices of the substrate and environment [28], which can be done by different procedures, or the introduction of an imaginary nanostructured layer, a reflection of the real layer [18].…”

“…In this case, to calculate the reflection and transmission spectra of the system with these parameters, the exact electrodynamics finite element method [22][23][24][25][26][27][28][29][30][31][32][33][34] is used in order to exclude the effect of made approximation (2) and the absence of multipole terms in the nanoparticle interaction tensor (6) (which are significant for the considered case of touching spheres) on the result. According to [29], for such geometrical parameters of the nanoaggregate, the considered analytical approach can be used only for estimating investigations.…”

Approximate Electromagnetic Cloaking of a Dielectric Sphere Using Homogeneous Isotropic Multi-Layered Materials

“…Recently, the concept of electromagnetic cloaking has drawn considerable attention concerning theoretical, numerical and experimental aspects [1][2][3][4][5][6][7][8]. One approach to achieve electromagnetic cloaking is to deflect the rays that would have struck the object, guide them around the object, and return them to their original trajectory, thus no waves are scattered from the body [1].…”

Three-Dimensional Polyhedral Invisible Cloak Consisting of Homogeneous Materials

“…Ideal isolated cloaks, such as spherical cloak [1], cylindrical cloak [3][4][5], elliptical cloak [6], and other columnar cloaks [7][8][9][10][11][12][13], etc., can work for any direction. Compared with the three-dimensional cloaks [1,13,14], the columnar cloaks can provide a perfect three-dimensional cloaking performance for wave incident from any direction. However, this requires the columnar cloak to be infinitely long, which is not easy for practical implementation.…”