A simple scheme of an illusion medium layer that transforms the stereoscopic image of an object (a golden apple) into that of the illusion (two green apples). (a) The golden apple (the actual object) enclosed with the illusion medium layer in the physical space. (b) Two green apples (the illusion) in the virtual space. Both physical and virtual spaces share the same virtual boundary (dashed curves).
Transformation optics offers an unconventional strategy to the design of metamaterial devices. In this letter, we propose a class of optical transformation media, illusion media, which can render the enclosed object invisible and generate one or more virtual objects as desired. An arbitrary object enclosed by such an illusion medium layer appears to be one or more other objects. We apply the proposed method to design two devices, one of which transforms an actual object into two virtual objects, and the other of which transforms a complicated metallic object into a virtual dielectric object with arbitrary material properties. Both illusion devices exhibit unusual electromagnetic behaviors as verified by full-wave simulations. Different from the published illusion devices which are composed of left-handed materials with simultaneously negative permittivity and permeability, the illusion media proposed in this work have positive permittivity and permeability. We also propose a method of amending function to eliminate the singularities of medium parameters in the illusion media. Hence the designed devices could be realizable using artificial metamaterials. The proposed method presents a major step towards the realization of illusion media.
Illusion media will change the scattering patterns of the enclosed object to make it appear like another object or multiple virtual objects. The new illusion media design has an advantage over previously proposed illusion media, in that it should be easier to fabricate. All permittivity and permeability components of our illusion media are finite and positive. Hence the presented approach makes it possible to realize the illusion media using artificial metamaterials.”
The parameter distributions of the illusion medium layer, (a) μ1, (b) μ2, and (c) “z. The scattered electric-field distributions in the computational domain for (d) a metallic square cylinder without the illusion medium layer; (e) a metallic square cylinder with the illusion medium layer; and (f) two dielectric square cylinders when the plane waves are incident horizontally from the left to the right.
In summary, we have presented a class of optical transformation media, illusion media, which can create one or more virtual objects by using metamaterials. In such illusion media, all components of constitutive parameters in the principle coordinate system are positive, hence the illusion media could be realizable using artificial structures. Moreover, we proposed a method of amending function to eliminate the singularity of medium parameters for the illusion devices. However, the changing range of some parameters is still relatively large in the current version. In the future work, we will investigate the illusion media with further simplified medium parameters so that the illusion devices can be experimentally verified.
The parameter distributions of the illusion medium layer, (a) μ1, (b) μ2, and (c) “z. The scattered electric-field distributions in the computational domain for (d) a bronze of a woman model without the illusion medium layers; (e) a bronze of a woman model with the illusion medium layers; and (f) a woman with material parameters ” = 3 and μ = 1 when the plane waves are incident in the horizontal direction from the left to the right.