Modeling of femtosecond photoacoustic non-destructive testing in AlCu nanofilms

Photoacoustic detection has shown excellent performance in measuring the thickness and detecting defects in metal nanofilms. However, during ultrafast photoacoustic detection, signal quality depends on both laser parameters and the physical properties of nanofilms. Therefore, it is important to study how physical processes evolve under different laser parameters to improve signal quality in various film materials. In this study, we have developed a comprehensive physical model that combines the Two-Temperature Model with the acoustic wave generation and detection model. Our numerical results, which are based on a 500-nm AlCu film composed of 95% aluminum and 5% copper, closely align with experimental results, demonstrating the validity of this model. This research offers valuable insights for improving photoacoustic signals in practical applications.