Asymmetric surface wave excitation through metasurface-edge diffraction

TL;DR

This paper demonstrates how truncating a metasurface and exploiting anisotropy can selectively excite different surface wave modes through edge diffraction, advancing control over surface wave excitation.

Contribution

It introduces a method to break symmetry in surface wave excitation using metasurface truncation and anisotropy, enabling selective mode excitation.

Findings

Truncation of metasurface influences surface wave excitation.

Inversion of wavevector component excites different surface modes.

Exact Wiener-Hopf solution confirms mode selectivity.

Abstract

The selective excitation of localized surface wave modes remains a challenge in the design of both leaky-wave and bound-wave devices. In this Letter, we show how the truncation of a metasurface can play an important role in breaking the spatial inversion symmetry in the excitation of surface waves supported by the structure. This is done by combining a large anisotropy in the dispersion relation and the presence of an edge which also serves as a coupling mechanism between the plane wave excitation and the induced surface waves. By resorting to the exact solution of the scattering problem based on a discrete Wiener-Hopf technique we show that by inverting the component of the impinging wavevector parallel to the truncation, two distinct surface waves are excited.