Patent ID: 7278315

Claim:
A laser-ultrasonic method for detecting a subsurface defect within a processed region of a metallic workpiece, comprising the steps of: generating a probe acoustic Rayleigh wave by directing a generation laser beam to a predetermined generation area on a surface of the metallic workpiece within the processed region; detecting a direct-arriving and a scattered acoustic Rayleigh wave via an interferometer and a detection laser beam that impinges the surface of the metallic workpiece at a detection spot which is within the processed region and has a predetermined spatial relationship to the generation area; repeating said step of generating and said step of detecting for a plurality of predetermined generation areas and detection spots on the surface of the metallic workpiece within the processed region; and comparing the direct-arriving and scattered acoustic Rayleigh waves detected for at least two predetermined detection spots to detect the subsurface defect within the processed region of the metallic workpiece.