Jay Sim

“Magneto-Mechanical Bilayer Metasurface with Global Area-Preserving Density Tunability for Acoustic Wave Regulation”

Advised by Prof. Renee Zhao

Abstract: Metasurfaces have immense potential in acoustics, optics, and electromagnetic applications due to their unique properties and ability to conform to curved substrates. Active metasurfaces have attracted significant research attention because of their on-demand tunable properties and performances through shape reconfigurations. They often achieve active properties through internal structural deformations, which often lead to changes in overall dimensions. This demands corresponding alterations of the conforming substrate, or the metasurface fails to provide complete area coverage, which can be a significant limitation for their practical applications. To date, achieving area-preserving active metasurfaces with distinct shape reconfigurations remains a prominent challenge. In this paper, we present magneto-mechanical bilayer metasurfaces that demonstrate area density tunability with area-preserving capability. The bilayer metasurfaces consist of two arrays of magnetic soft materials with distinct magnetization distributions. Under an external magnetic field, each layer behaves differently, which allows the metasurface to reconfigure its shape into multiple modes and to significantly tune its area density without changing its overall dimensions. The area-preserving multimodal shape reconfigurations are further exploited as active acoustic wave regulators to tune bandgaps and wave propagations. The bilayer approach thus provides a new concept to the design of area-preserving active metasurfaces for broader practical applications.