An acoustic apparatus and method for microscopic imaging and spectroscopy. The apparatus includes a plurality of devices for exciting an object of interest so that acoustic waves are propagated from the object. These devices include lasers, x-ray sources, microwave generators, ultraviolet sources, and...http://www.google.co.uk/patents/US4267732?utm_source=gb-gplus-sharePatent US4267732 - Acoustic microscope and method
