Experimental Verification of Shape‐Independent Surface Cloak Enabled by Nihility Transformation Optics

Abstract

The manipulation of electromagnetic surface waves on interfaces that have arbitrary shape geometrical disorders has gained a lot of interest owing to its wealth of advantages in modern photonics and plasmonics devices. In this paper, based on the well‐established method of transformation optics, a reconfigurable cloak that is competent in guiding the propagation of surface plasmon polaritons (SPPs) at a distorted metal‐dielectric interface is introduced. The presented cloak consists of a homogeneous anisotropic material, dubbed as optic null medium (ONM) that is independent of the cloak geometrical shape. Whilst the homogeneity property of ONMs leads to the feasibility in fabrication, the shape independency feature yields an on‐demand control over the flow of SPPs, simply by changing the shape of the cloak while leaving its constituent material unchanged. In order to authenticate the idea, a triangular‐shape SPP cloak is designed and fabricated experimentally at microwave frequency. It is observed that by utilizing the designed cloak almost total transmission can be obtained from the distorted interface. The unique designing approach introduced here may open a new horizon to nano‐optics and downscaling of photonic circuits.

Multiband Omnidirectional Invisibility Cloak

“…These two properties make TIMs an ideal platform to implement full‐parameter TO devices. [ 20 ] In the practical implementation, TIMs for the transverse magnetic (TM) wave incidence can be realized through either a multilayer of metal/epsilon‐near‐zero metamaterial alternating structures [ 7 , 10 , 20 , 24 ] or a subwavelength metallic slot array working at the Fabry‐Pérot (FP) resonance frequencies. [ 5 , 25 , 26 ] Nonetheless, all full‐parameter cloaks experimentally implemented thus far only work at a single frequency.…”