Beyond the limitations of passive acoustic metamaterials using dispersion engineering and complex frequency excitations

In this talk, we discuss our latest results on acoustic metamaterials, in which we theoretically introduce and experimentally demonstrate complex dispersion engineering of acoustic waves on elastic metamaterials, and excitation at complex frequencies to realize virtual absorption and virtual gain. Our results open new avenues for sound manipulation using metamaterials, going beyond conventional limits. We will discuss the basic principles behind the described phenomena and the implications for technologies.