Soft acoustic metamaterials by design

The link between the constitutive parameters of dissipative media supporting (un)usual wave motions and the plane wave motion exhibition, has been established in order to propose a tool for designing functional materials able to control acoustic wave propagation. In this context, we propose a new route to produce a large amount of Mie resonators possessing very low sound speed (100 m s-1) by means of soft matter techniques coupled with microfluidics. Their random distribution in a water-based gel matrix (with a much higher sound speed, 1500 m s-1) should confer specific effective acoustic properties on these “ultra-slow” Mie resonator suspensions, such as negative acoustic refractive index.