Robust Large Dimension Terahertz Cloaking

Abstract

A large scale homogenous invisibility cloak functioning at terahertz frequencies is reported. The terahertz invisibility device features a large concealed volume, low loss, and broad bandwidth. In particular, it is capable of hiding objects with a dimension nearly an order of magnitude larger than that of its lithographic counterpart, but without involving complex and time-consuming cleanroom processing.

CLOAKING AND INVISIBILITY: A REVIEW (Invited Review)

“…Another possible route is to modify the carpet cloaking transformation in order to obtain a variant of carpet cloaking that can be realized with directly available natural anisotropic materials, but does not suffer from the lateral shift problem, making it possible to use carpet cloaking to hide bigger objects [116,117]. Such modified carpet cloaks were implemented with affine transformations using bi-refringent natural dielectric crystals, calcite in the visible [118,119] and saphire at THz [120]. With this method, 2D carpet cloaking of macroscopic objects is possible in a wide range of incidence angles and without lateral shift, but only for one polarization of light.…”

Optical transformation design of waveguide bends and splitter in photonic crystals

“…The constructive parameters for the proposed bending and splitting structure are anisotropic and spatially invariant in each block, and some natural crystals [35] and artificial dielectric layers [33,36] can be taken as the effective medium to realize the anisotropy. The working bandwidth of the presented waveguide bender and splitter is limited only by the band gaps of the background photonic crystal and dispersion of the constitutive dielectrics, thus exhibiting low-loss in a wideband range.…”

Recent advances in transformation optics

“…The demonstrated cloaks at microwave and terahertz frequencies are physically large, and range from centimetres to millimetres. 81,86,[103][104][105] In other words, they are in the order of around 100 wavelengths or less. However, how to observe the cloaking effect with naked eye, i.e., to cloak a macroscopic object in the visible regime was thought extremely challenging.…”