A perspective on meta-boundaries

TL;DR

This paper reviews the recent advances in the design and categorization of meta-boundaries with surface conductivity, highlighting their role in controlling light-matter interactions and future research directions.

Contribution

It provides a comprehensive categorization of meta-boundaries and reviews recent developments, offering insights into their potential for manipulating light-matter interactions.

Findings

Classification of meta-boundaries into four types

Review of recent developments for each meta-boundary type

Outlook on future research combining meta-boundaries and metamaterials

Abstract

The judicious design of electromagnetic boundary provides a crucial route to control light-matter interactions, and it is thus fundamental to basic science and practical applications. General design approaches rely on the manipulation of bulk properties of superstrate or substrate and on the modification of boundary geometries. Due to the recent advent of metasurfaces and low-dimensional materials, the boundary can be flexibly featured with a surface conductivity, which can be rather complex but provide an extra degree of freedom to regulate the propagation of light. In this perspective, we denote the boundary with a non-zero surface conductivity as the meta-boundary. The meta-boundaries are categorized into four types, namely isotropic, anisotropic, biisotropic and bianisotropic meta-boundaries, according to the electromagnetic boundary conditions. Accordingly, the latest development for these four kinds of meta-boundaries are reviewed. Finally, an outlook on the research tendency of meta-boundaries is provided, particularly on the manipulation of light-matter interactions by simultaneously exploiting meta-boundaries and metamaterials.