A Complete Acoustic Microscopical Analysis of Multilayered Specimens

Abstract

A theoretical analysis is carried out to synthesize the V(z) curves of multilayered solids immersed in water. Solid layers attenuate ultrasound and change its phase. A liquid layer may be located in between two solid layers. The goal of this analysis is to avoid the three major simplifying assumptions of the presently available techniques, as paraxial approximation, assumption of perfect reflection and ambiguous pupil function or incident field strength variation in the illuminated region. Presently available techniques developed for conventional acoustic microscopes can avoid some but not all of these assumptions for computing the V(z) curve. In this paper, the analysis is carried out for a spherical cavity lens with a large aperture angle. The V(z) curve for a uniform glass half-space is synthesized analytically and compared with experimental results. Analytical results are also presented for chromium plated glass specimens and biological cells on uniform glass half-space. Such an exact analysis of multilayered specimens is necessary for material science research as well as cell research in biology, because advanced engineering composite materials and biological cells in culture have multiple layers.