Abstract
Directivity patterns of laser-generated longitudinal waves in carbon steel and cement paste have been determined experimentally, for laser power densities both ablation and thermoelastic regime on the specimen surface. Comparison of experimental results with theory made it clear that 1) the theoretical prediction of the ablation regime is not in agreement with our experimental results on the untouched surface in both the carbon steel and the cement paste specimen, 2) directivity patterns dependent on the detecting frequency, 3) directivity patterns are independent of the laser incident angle on the target's surface.
