3D Printed Quadratic Residue Metadiffuser – Design and Measurements of an Optimized Deep-Subwavelength Sound Diffuser
* Presenting author
Heavily based on slow sound propagation produced by the strong dispersion in waveguides loaded by side branch resonators, metadiffusers take the form of slotted panels with thin slits, each one loaded by a set of Helmholtz resonators. This type of structure was previously used as deep-subwavelength perfect absorber. Instead of focusing on absorptive and transmitting properties, metadiffusers emphasize on perfect or pseudo-perfect reflection of sound. Here a particular interest is given to the scattering patterns obtained by the customization of metamaterial’s geometry. The deep-subwavelength nature of the structure leads to dimensions 20 to 46 times smaller than the design wavelength, i.e. about 1/20th to 1/10th of the thickness of traditional designs. This presentation aims at introducing the physical aspects of sound propagation in and out of the metadiffuser, emphasizing on strong dispersion relations, on the consequent deep-subwavelength features arising from the slow sound propagation, and on the custom scattered fields. This theoretical overview will then be paired with numerical and experimental data of a 3D-printed quadratic residue metadiffuser. Finally, potential applications of such structures will be discussed in critical industry environments.