Multi-physics and trans-physics metamaterials

Metamaterials are artificially engineered structures with high designability and flexibility and can exhibit unique properties that surpass the natural materials. Initially demonstrated in the microwave regime, the metamaterials have subsequently facilitated advancements across diverse physical domains, encompassing optics, acoustics, and beyond. More importantly, the metamaterials offer unprecedented opportunities to manipulate the behaviors of multiple physical waves simultaneously, as well as to manipulate one physical wave by using the others, giving rise to the rapid development of multi-physics and trans-physics metamaterials. Here, we focus on the recent advancements in both multi-physics and trans-physics metamaterials, from basic working mechanisms to realized functions and emerging applications. For multi-physics metamaterials, we illustrate the progress in acoustic-microwave dual-physics metamaterials, light-microwave dual-physics metamaterials, and several triple-physics metamaterials to elucidate how a single metamaterial structure can simultaneously manipulate two or more types of physical waves. For trans-physics metamaterials, we highlight four representative categories: light-controlled microwave metamaterials, light-controlled optical metamaterials, light-controlled acoustic metamaterials, and acoustic-controlled microwave metamaterials, demonstrating how the metamaterials can be utilized to achieve trans-physics wave manipulations and hybrid signal conversion and information transmission. Finally, we conclude by identifying key challenges, enabling technologies and future opportunities of multi-physics and trans-physics metamaterials.