Acoustic microscopy is a non-destructive, non-invasive technique for revealing microstructure and detecting changes in elastic properties of samples on a microscopic scale. This technique provides information not available through other techniques, and it has broad applications to biomedical research and materials science. An acoustic microscope has been developed which makes use of a scanning laser beam as a remote sensing microphone. Acoustic and optical micrographs of a specimen are simultaneously produced on TV monitors in real time, thereby enabling dynamic activity to be studied.
Lawrence W. Kessler,
"Principles And Applications Of The Scanning Laser Acoustic Microscope", Proc. SPIE 0104, Multidisciplinary Microscopy, (26 August 1977); doi: 10.1117/12.955428; https://doi.org/10.1117/12.955428