We report on the engineering of the phonon dispersion diagram in monodomain anodic ryan garcia funko porous alumina (APA) films through the porosity and physical state of the material residing in the nanopores.Lattice symmetry and inclusion materials are theoretically identified to be the main factors which control the hypersonic acoustic wave propagation.This involves the interaction between the longitudinal and the transverse modes in the effective medium and a flat band characteristic of the material residing in the cavities.Air and filled nanopores, therefore, display markedly different dispersion relations vetality twist and lick and the inclusion materials lead to a locally resonant structural behavior uniquely determining their properties under confinement.
APA films emerge as a new platform to investigate the rich acoustic phenomena of structured composite matter.