Tuning optical properties of metasurface via piezoelectric effect

The authors theoretically propose a design for electrically tuning a metasurface based on piezoelectric actuation. The design comprises 2D gap-plasmon elements arranged periodically on a piezoelectric substrate which controls the period between them. The technique is numerically studied for a metasurface that anomalously reflects an incident p-polarised wave by 30 degrees at the optical communication wavelength, 1550 nm. The dynamic behaviour of the system is investigated for two main applications; (a) steering the reflection angle and (b) retrieving the reflection angle for an incident wave of a shifted wavelength. It is demonstrated that a reflected beam can cover an angle of similar to 3 degrees upon a strain of <3.3%. It is also shown that at the same strain value, the reflection angle is retrieved for a wavelength error of +/- 50 nm. These results suggest a potential to design large-bandwidth, reconfigurable metasurfaces that are integrable with planar opto-electromechanical devices.