W. Zapka, A.C. Tam, et al.
Microelectronic Engineering
We describe the generation and detection of short acoustic pulses (∼10-ns widths) in opaque plates, using weak laser pulses (less than 1-mJ energy) for excitation. The longitudinal, shear, and surface acoustic waves generated by a single laser pulse can be time resolved by using a thin-film piezoelectric transducer, and acoustic mode conversions at surfaces are clearly observable. This new photoacoustic material testing technique is useful for fast ultrasonic measurements or for detecting deep subsurface flaws.
W. Zapka, A.C. Tam, et al.
Microelectronic Engineering
Felix Grawert, Sebastian Kobras, et al.
SPIE Optical Science and Technology 2000
A.C. Tam, Holger Schroeder
Journal of Applied Physics
A.C. Tam, H. Sontag
Applied Physics Letters