Noncontact determination of transverse isotropic elastic moduli in polyimide thin films using a laser based ultrasonic method

Abstract
A transient gratinglaser ultrasonic method known as real‐time impulsive stimulated thermal scattering is used to excite and monitor Lamb acoustic waveguide modes in free‐standing thin polyimide films which are known to have transverse isotropic symmetry. The dispersion of these Lamb modes is used to accurately evaluate both the in and out‐of‐plane elastic moduli.