Acoustic microscopic study on local elastic properties of the mini-sample

The output of scanning acoustic microscope consists of the reflected sound wave of paraxial beams and the leaky surface elastic wave, which is sensitive to the change of the surface elastic properties. When there are interface or cracks on the surface of mini-sample, the surface wave will be reflected by the interface, and in result of interference of reflected leaky wave with paraxial wave, the interference rings will be obtained. By these rings we will get possible to evaluate velocity of the Rayleigh wave on mini-sample.