A metasurface with bidirectional hyperbolic surface modes and position-sensing applications

Chuandeng Hu,Yingzhou Huang,Rui Tong,Li Wang,Shuxia Wang,Xiaoxiao Wu,Bo Hou,Weijia Wen

doi:10.1038/s41427-018-0047-0

Abstract

We have theoretically and experimentally studied resonance-induced hyperbolic metasurfaces and proved that they offer an efficient way to introduce Fano-resonance and decrease the Q-factor in our system in order to create hyperbolic isofrequency contours (IFCs) along two orthogonal directions. A metasurface with a continuous topological transition for such IFCs has been designed and experimentally implemented. In particular, two independent collimation frequencies can be found to correspond to the transition frequencies in orthogonal directions. As a consequence, we experimentally demonstrated that the metasurface can function as a position sensor by utilizing bidirectional hyperbolic surface waves, introducing a new avenue for coordinate sensing.

Highlights

Surface electromagnetic (EM) waves on twodimensional interfaces of dissimilar mediums have been a predominant topic of interest among researchers due to their unique features[1,2,3]
The geometric parameters of the unit cell were chosen as in Fig. 1a, and the excitation unit was composed of microstrip lines to excite surface EM waves
The metallic patterns were printed in the dielectric slab with 35 μm thick copper and were covered by a negligible thickness of solder on the copper surface to prevent oxidation

Summary

Introduction

Surface electromagnetic (EM) waves on twodimensional interfaces of dissimilar mediums have been a predominant topic of interest among researchers due to their unique features[1,2,3]. Metals can be regarded as perfect electric conductors (PECs) in low-frequency ranges, e.g., the farinfrared, microwave, and terahertz regimes. In these lowfrequency regimes, SPPs become very weakly confined Zenneck waves, and the evanescent fields can extend over several wavelengths[8,9]. Metallic/dielectric layers composed of subwavelength, regularly arranged metallic wires known as metasurfaces bind EM fields to individual interfaces with unique anisotropic dispersions that, along with SPPs and SSPPs, play important roles in manipulating near-field light scattering[11,12,13,14]

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Results

Conclusion