Localized transformation optics devices

Abstract

We propose a strategy to design localized transformation optics devices, and take the localized invisibility cloaks as examples to illustrate their special properties. Different from the global cloaks that make the enclosed objects completely invisible, the localized cloaks will conceal the scattering signals of certain parts of the enclosed objects and keep the signals of remaining parts being unchanged. We design, fabricate, and measure a localized dc invisibility cloak in the steady currents by using the localized transformation electrostatics. Simulation and experimental results show that the potential distribution outside the localized dc invisibility cloak is exactly the same as that of a part of the cloaked object.

Spatial transformation-enabled electromagnetic devices: from radio frequencies to optical wavelengths

“…The cloak is an inhomogeneous and anisotropic material coating that bends the incident wave around the object encompassed inside the coating, such that the object cannot be observed from the outside [7]. Inspired by the original cloaking design [2,8], many variations of cloaks have been proposed using modified coordinate transformations, including cloaks with different shapes and simplified material parameters [9][10][11][12], directional cloaks [13,14], conformal mapping-based isotropic cloaks [15], complementary media-enabled cloaks at a distance away from the object [16], localized cloaks that hide only a part of the object [17], carpet cloaks that give much broader operational bandwidth [18][19][20][21][22][23], macroscopic cloaks that hide electrically large objects [24][25][26], broadband cloaks for non-Euclidean space [27], all-dielectric cloaks [28][29][30] and so on. The more general illusion device, however, transforms the scattering perception of an object into that of another pre-defined target object [31][32][33].…”