Acoustic metamaterial absorbers: The path to commercialization

Acoustic metamaterial represents the synergism between wave physics and designed geometric structures, aimed at novel acoustic properties. For the important functionality of acoustic absorption, metamaterials face the challenges posed by a mature, existing group of absorbing materials that have proven their effectiveness. Can the metamaterials do better? If so, at what price? This article aims to answer these important questions. In particular, it is shown that the critical advantage offered by metamaterial absorbers lies in the tunability of the absorption spectrum to fit the needs of the client, in conjunction with a minimum absorber thickness set by the causal constraint. By overcoming the obstacles set by the mass production cost, acoustic metamaterial absorbers have now entered the commercialization stage. We give three examples of the commercialized applications together with their underlying working principles and conclude with some observations.