A THIRD WAY TO CLOAK AN OBJECT: COVER-UP WITH A BACKGROUND OBJECT (Invited Paper)

Abstract

Abstract-Based on a space folding transformation, we propose a new way to hide an object in full space, namely, to cover-up the scattering of the hidden object with the scattering of a background object so that only the scattering of the background object can be detected by an outside observer and the hidden object disappears electromagnetically (a very weak "ghost image" or perturbation may appear inside the strong background object image in an experiment). The present method is essentially different from previous methods of cloaking an object, namely, the optically isolated cloak and the scattering cancellation cloak, and thus provide a third way to cloak an object. Unlike all the previous methods of cloaking, the present full-space omni-directional invisibility simultaneously has the following features: (i) the hidden object can "see" the outside world without being detected; (ii) the cloak can still work when some characteristics (e.g., shape and medium) of the hidden object change; and (iii) there is no need to know the information of the incident wave in advance. The present work furthers efforts to achieve invisibility and conceal an object in a real environment in full space.

Transformation Optics: From Classic Theory and Applications to its New Branches

“…[140] The third type of cloak is a scattering overlapping cloak, which was first proposed by Sun and He in 2014. [141] In this kind of cloak, we need a strong scattering object as a background object. The concealed object is set around the background object.…”

Surface Transformation With Homogenous Optic-Null Medium

“…Many scattering-related problems can be tackled with the help of TO, e.g., cancelling the scattering pattern of an arbitrarily shaped object [1,[5][6][7], steering the radiation angle [8,9], creating the scattering illusions [10][11][12][13]. Due to the development of metamaterials (i.e., a kind of artificial materials composed of some subwavelength structures) [14], many devices designed by TO have been fabricated and experimentally demonstrated.…”

Overlapping illusions by transformation optics without any negative refraction material

“…Transformation optics (TO) is a powerful tool to design electromagnetic/optical devices with pre-designed function to achieve an unprecedented controlling of the light wave 1 2 3 . Many novel devices have been designed or even experimentally demonstrated by TO including invisibility cloaking 1 4 5 6 , perfect imaging device 7 8 , power combination 9 10 11 12 13 14 , radiation suppression 15 and other optical illusions 16 .…”