Three-dimensional visible-light invisibility cloak

TL;DR

This paper presents a novel 3D visible-light invisibility cloak that simplifies design by using homogeneous, isotropic materials, enabling large-scale cloaking of objects from multiple viewpoints.

Contribution

The authors develop a 3D transformation and discretization method that reduces electromagnetic coupling, allowing practical large-scale visible-light cloaks with simple materials.

Findings

Successfully cloaked a large spherical object from three directions.

Used homogeneous, isotropic materials for the cloak.

Achieved significant simplification in 3D invisibility design.

Abstract

The concept of an invisibility cloak is a fixture of science fiction, fantasy, and the collective imagination. However, a real device that could hide an object from sight in visible light from absolutely any viewpoint would be extremely challenging to build. The main obstacle to creating such a cloak is the coupling of the electromagnetic components of light, which would necessitate the use of complex materials with specific permittivity and permeability tensors. Previous cloaking solutions have involved circumventing this obstacle by functioning either in static (or quasi-static) fields where these electromagnetic components are uncoupled or in diffusive light scattering media where complex materials are not required. In this paper, we report concealing a large-scale spherical object from human sight from three orthogonal directions. We achieve this result by developing a three-dimensional (3D) homogeneous polyhedral transformation and a spatially invariant refractive index discretization that considerably reduce the coupling of the electromagnetic components of visible light. This approach allows for a major simplification in the design of 3D invisibility cloaks, which can now be created at a large scale using homogeneous and isotropic materials.