Real-time optical characterization of surface acoustic modes of polyimide thin-film coatings

Abstract

A modification of the optical technique of impulsive stimulated thermal scattering that allows real-time data acquisition is introduced. The method is used to characterize the pseudo-Rayleigh acoustic modes of thin (∼1 μm) polyimide films attached to silicon substrates and its potential use as a means for extracting the elastic constants of thin-film coatings is demonstrated.