Coherently time-varying metasurfaces

TL;DR

This paper introduces time-coherently modulated metasurfaces that enable control over wave reflection, absorption, and transmission across multiple frequencies, including incoherent illuminations, with applications in designing broadband perfect absorbers and remote tuning.

Contribution

It presents a new class of metasurfaces modulated in time coherently with incident waves, allowing multi-frequency control and overcoming static bandwidth limits.

Findings

Design of multi-frequency perfect absorbers

Demonstration of remote tuning of absorption levels

Control of wave interference at multiple frequencies

Abstract

Known coherent metasurfaces control interference of waves of a given frequency with other coherent waves at the same frequency, either illuminating from a different direction or created as intermodulation products. In this paper, we introduce a class of metasurfaces that are modulated in time coherently with the illuminating radiation. Importantly, such modulation opens a possibility to control reflection, absorption, and transmission at multiple frequencies, including illuminations by two or more incoherent waves. In particular, we study dynamic resistive layers and show how to use them to design thin multi-frequency perfect absorbers that overcome the bandwidth limit for static linear absorbers. Furthermore, we demonstrate possibilities of remote tuning of the absorption level. We hope that this work opens up novel avenues in wave engineering using coherent modulation of metasurface parameters.