Acoustic microscopy: present and future

After nearly ten years of research and development, the acoustic microscope has now reached the point where its resolution is far superior to that of the optical microscope. Several commercial firms are now in the process of manufacturing scanning acoustic microscopes, and it will not be long before these are available on the open market. In the paper, we review the basic operating principles of the microscope and describe some of the achievements made over the past decade. The paper is concluded by a discussion of possible areas for future advance.