A THEORETICAL-ANALYSIS OF ACOUSTIC MICROSCOPY WITH CONVERGING ACOUSTIC BEAMS

A theoretical analysis is carried out to synthesize acoustic material signatures (AMS) of solid plates immersed in water. The distinctive feature of this analysis is that it avoids three major simplifying assumptions of the presently available techniques, which are paraxial approximation, assumption of perfect reflection and Gaussian summation of the incident field. Presently available techniques can avoid some but not all of these simplifying assumptions for computing the AMS. In this paper the analysis is carried out for low-frequency acoustic waves generated by a cylindrical transducer without a lens rod. Reasons for these changes in the conventional acoustic microscope geometry is given. The AMS is synthesized for an aluminum plate in presence as well as in absence of water on its one side. As expected a significant difference is observed between the signatures generated under these two situations.