THE ACOUSTOOPTIC INTERACTION IN THE INTERFEROMETRIC MEASUREMENT OF ULTRASONIC TRANSDUCER SURFACE MOTION

The determination of the actual vibration distribution of an ultrasoni c transducer radiating into a liquid is identified as one of the major unresolved questions of precision ultrasonic science. Direct measurem ent of the surface vibration distribution using optical interferometry is not possible due to the piezo-optic effects of the radiating ultra sonic beam on the liquid through which the optical interferometer beam must travel. An analysis is presented which relates the actual vibrat ion distribution to that which would appear to be measured. The possib ility of inverting this process to retrieve the original distribution is identified.