Multi-element transducer dedicated to quantitative acoustic microscopy imaging

This paper described an innovative multi-element sensor dedicated to scanning acoustic microscopy and allowing the mechanical characterization of elastic materials with Poisson's ratio comprised between 0.2 and 0.35. While such measurement is already possible at a single location, the large amount of data necessary to perform the properties' identification prohibits the implementation of quantitative imaging. A multi-element sensor was then developed in order to considerably lower the needed data. This results in much faster acquisitions and enables a high-resolution cartography of mechanical properties. The proposed sensor allows the separation of the two main waves generated by an acoustic microscope namely specular and surface Rayleigh waves, the latter carrying the mechanical information. A Rayleigh wave velocity measurement protocol is then proposed and a first image of local Young modulus of a chromium sample is obtained.