Numerical Analysis of Ultrafast Acoustic Wave Generated by Picosecond Laser Pulse in Multilayers

A numerical approach is presented to describe how ultrafast acoustic wave is generated by laser pulse in multilayer thin films. Transient surface displacement obtained through simulation is confirmed by the experiment measurement data. Analyzing results with the two temperature model, it is able to determine the interfacial thermal resistance. Optical reflectance changes are obtained by combining the contributions of thermal and acoustic effects, which agree with the experiment well.