Epicentral and near epicenter surface displacements on pulsed laser irradiated metallic surfaces

The elastic deformations associated with the pulsed laser, photothermal heating of an aluminum alloy surface have been measured within the irradiated region using a Michelson-type interferometer. The displacements within this region have been measured and have been compared to calculations based on temperature-rate dependent thermoelasticity theory. The quantitative agreement between calculation and experiment shows the contributions of the local thermal expansion and the propagating acoustic modes on the overall displacements at the epicenter and near the epicenter of the irradiated region. Nonlinear effects on the propagation of the near-field surface acoustic wave may be present.