Controlling surface waves with temporal discontinuities of metasurfaces

TL;DR

This paper explores how sudden temporal changes in metasurface impedance can control, amplify, or halt surface waves, enabling novel wave manipulation techniques with potential applications in wave generation and control.

Contribution

It introduces the concept of controlling surface waves through temporal discontinuities of metasurfaces, demonstrating new phenomena like wave velocity control, static magnetic field freezing, and wave coupling.

Findings

Surface wave velocity can be fully controlled by switching surface capacitance.

Switching from capacitive to inductive boundary halts surface waves, creating a static magnetic field.

Temporal impedance jumps couple free-space waves to surface waves, acting like a spatial prism.

Abstract

In this paper, we investigate the scattering of surface waves on reactive impedance boundaries when the surface impedance undergoes a sudden change in time. We report three exotic wave phenomena. First, it is shown that by switching the value of the surface capacitance of the boundary, the velocity of surface waves can be fully controlled, and the power of reflected and transmitted surface waves are amplified. Second, we show that when a capacitive boundary is switched to an inductive one, the surface wave stops completely, with a "frozen" static magnetic field distribution. The static magnetic fields are "melt" and restore propagating surface waves when the boundary is switched back to a capacitive one. Third, we show that temporal jumps of the boundary impedance couple free-space propagating waves to the surface wave, which is an analog to a spatial prism. These interesting effects enabled by temporal jumps of metasurface properties open up new possibilities for the generation and control of surface waves.