Space-Time Metasurfaces: Unleashing the Potential of Four-Dimensional Wave Engineering

This study investigates a transformative approach by infusing temporal variation into static metasurfaces, creating dynamic systems capable of four-dimensional manipulation of both spatial and temporal characteristics of electromagnetic waves. We explore recent advancements in the analysis and functionalities of Space-Time (ST) interfaces, metasurfaces, and slabs designed to disrupt reciprocity, generate new frequencies, and amplify signal power. Examining various operational aspects of ST metasurfaces, we explore scattering and diffraction at ST interfaces, ST sinusoidally varying surfaces and slabs, as well as transmissive and reflective ST metasurfaces. The paper high-lights potential applications, offering insights into the promising capabilities of dynamic space-time metamaterials for the future of electromagnetic wave engineering.