Fourier transform approach to materials characterization with the acoustic microscope

Abstract

A general method is presented for characterization of elastic properties of materials with the reflection acoustic microscope. The material acoustic reflectance function and the acoustic microscope focus curve [V(z)] are shown to be a Fourier transform pair. By measurement of both phase and amplitude, the complex V(z) curve can be recorded. These data can then be inverted to obtain an estimate of the reflectance function. This method allows calibration of individual acoustic lenses and is experimentally demonstrated with a 50‐MHz acoustic microscope and a synchronous phase detection system.