Pulsed laser characterization of multicomponent polymer acoustic and mechanical properties in the sub-GHz regime

We investigated the acoustic properties in the sub-GHz frequency regime of a multilayer system comprising alternating 100-nm scale TiO₂/poly(methyl methacrylate) (PMMA) layers through a laser photoacoustic method, impulsive stimulated thermal scattering (ISTS). The acoustic dispersion curves were determined, and the mechanical properties were extracted from the experimental results.