A Tunable Metasurface with Switchable Functionalities: From Perfect Transparency to Perfect Absorption

Abstract

A thin screen exhibiting dynamically switchable transmission/absorption functionalities is highly desired in practice. However, a trilayer transmissive metasurface with active elements controlled in a uniform manner cannot exhibit independently controlled transmission and absorption properties due to intriguing interplays between the scattering and absorbing properties in systems exhibiting inversion symmetries. This motivates to employ the coupled‐mode theory to establish a generic phase diagram for such transmissive metasurfaces with active elements loaded in different layers tuned independently and to guide researchers design tunable metadevices with completely decoupled transmission/absorption responses. Based on such a phase diagram, a microwave metasurface is designed/fabricated with PIN diodes incorporated, and it is experimentally demonstrated that its functionality can switch from perfect transparency to perfect absorption, controlled by external voltages applied across the diodes. In addition to finding immediate applications in practice (e.g., smart radomes), the results of this study also provide a new type of tunable meta‐atom for building metasurfaces with flexible wave‐front control abilities.

Toward Intelligent Metasurfaces: The Progress from Globally Tunable Metasurfaces to Software‐Defined Metasurfaces with an Embedded Network of Controllers

“…Control over these complex coefficients, locally or globally, can give rise to a multitude of tunable functionalities and respective applications, for example, absorber, polarizer, anomalous reflector, etc. Fundamental physical properties of the resonant unit cells underlie the operation regimes, that is, when a reflective metasurface can operate as a tunable absorber/ reflector [10,11] or when a transmissive metasurface is transparent/absorptive, [12] as well as the transitions between them, [13] as can be shown with, for example, coupled mode theory.…”

High-Performance Transmissive Broadband Vortex Beam Generator Based on Pancharatnam–Berry Metasurface

“…To address this issue, multilayer meta-atoms were widely used to build transmissive metasurfaces. In [42][43][44], multilayer meta-atoms are explained by the coupled-mode theory, which reveals the inherent physics governing the transmission properties in multilayer meta-atoms of distinct types. It is found that meta-atoms with a particular type can provide transmission phases covering only a particular range.…”

A simple Mie-resonator based meta-array with diverse deflection scenarios enabling multifunctional operation at near-infrared

“…Noticeably, the geometric-phase metasurfaces are intrinsically multifunctional, since they may merge deflection and polarization manipulation in one step, e.g., see [48,55,56]. The tunable and reconfigurable metasurfaces may enable even more diversity in terms of functionality [57][58][59][60]. Nevertheless, the capability of the structures which do not comprise tunable components in multifunctional operation is also very high.…”