Colloidal systems: a promising material class for tailoring sound propagation at high frequencies

In this paper we report on the phononic properties of mesoscopic colloidal materials. Using high resolution Brillouin light scattering (BLS) the resonance modes of submicron particles as well as the dispersion relations of their ordered assemblies in a liquid matrix are studied. Two different kinds of very recently realized acoustic bandgaps are presented. In colloidal mixtures, the particle acoustic resonances are independent of composition.