Coherently Time-Varying Metasurfaces

Known coherent metasurfaces control the 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. 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 multifrequency 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 alternative avenues in wave engineering using coherent modulation of metasurface parameters.

Automated summary

This paper introduces a class of time-coherent metasurfaces and explores their ability to control reflection, absorption, and transmission at multiple frequencies, including illuminations by incoherent waves. The authors also study dynamic resistive layers and demonstrate how to use them to design thin multifrequency perfect absorbers, as well as the possibility of remote tuning of the absorption level.