A Broadband and omnidirectional electromagnetic wave concentrator with gradient woodpile structure

Ming Yin,Xiao Yong Tian,Ling Ling Wu,Di Chen Li

doi:10.1364/oe.21.019082

Abstract

We present the first realized three-dimensional (3D) practical implementation of the so called "optical black hole" in microwave frequencies, an electromagnetic (EM) concentrator. The 3D EM wave concentrator was designed with non-resonant gradient index (GRIN) 3D woodpile photonic crystals (PCs) structure in metamaterial regime, and fabricated by Stereolithography (SL) process. Omnidirectional EM wave capture and absorbing ability of the device in a broad bandwidth (12GHz-15GHz) were validated by full-wave simulation and experiments. Such devices may have applications in microwave energy harvesting and radiation detector.

Highlights

Artificial metamaterials made scientists magicians in the EM wave world with Transformation Optics (TO) [1,2], the magic wands in their hands
TO theory has demonstrated its magic power in the design of novel EM devices with specific material parameters distribution profile, which offered a way to manipulate the propagation of EM waves
The shell with radially varying permittivity profile was designed with non-resonant 3D gradient index (GRIN) woodpile photonic crystals (PCs) structures in metamaterial regime

Summary

Introduction

Artificial metamaterials made scientists magicians in the EM wave world with Transformation Optics (TO) [1,2], the magic wands in their hands. TO theory has demonstrated its magic power in the design of novel EM devices with specific material parameters distribution profile, which offered a way to manipulate the propagation of EM waves. The isotropic and non-resonant approach proposed by Narimanov and Kildishev [12] was further demonstrated theoretically [14,15,16,17] and implemented in microwave regime [18,19,20]. The so called “black hole” devices behave more like omnidirectional and broadband EM wave concentrators. 3D implementation of such devices would broaden the potential applications, but it increases the difficulty in design and fabrication. The shell with radially varying permittivity profile was designed with non-resonant 3D gradient index (GRIN) woodpile photonic crystals (PCs) structures in metamaterial regime. The 3D EM wave concentrator proposed may find potential applications in energy harvesting and radiation detector

Design of the 3D EM wave concentrator

Simulation results

Realization and experimental performance of the 3D EM wave concentrator

Conclusion