Optical imaging of transient acoustic fields generated by piezocomposite transducers

Transient surface displacements of 1-3 piezocomposite transducers are measured and their correlative effects on the diffraction of the transmitted pulses are studied. The displacements of the surface of a 210 /spl mu/m pitch piezocomposite are probed with a heterodyne, optical interferometer. An animate sequence is then built from the stored transient displacements so that each frame shows the instantaneous state of the surface of the piezocomposite. Such an animation proves to be a powerful analysing tool which provides a real insight into the piezocomposite's impulse behavior. Finally, the ultrasonic field transmitted in water and measured by the same optical probe is compared with simulations based on the diffraction impulse theory. The results of that comparison clearly show that, as far as diffraction is concerned, a piezocomposite transducer behaves like a homogeneous material.<>