Bendable disordered metamaterials for broadband terahertz invisibility

Abstract

Here, we experimentally demonstrate a bendable cloaking structure composed of obliquely stacked planar metallic shells that individually enclose the objects to be hidden. The ensemble of shells acts as a disordered oblique grating that can be bent to form a curved structure; this bendable cloaking structure exhibits broadband invisibility from 0.2 to 1.0 THz, and the curved cloaking structure is functionally effective for incident angles ranging from -10° to 30°. A wide range of practical applications exists that would require hiding cloaked objects with sizes of the order of hundreds of microns, which are smaller than the sizes of the metal shells. In principle, similar cloaking effects can be achieved for a broad bandwidth of frequencies ranging from infrared to radio waves.