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 trans mitted pulses are studied, The displacements of the surface of a 210 m u m pitch piezocomposite are probed with an heterodyne, optical interf erometer, 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 powerf ul analysing tool which provides a real insight into the piezocomposit e's impulse behavior, Finally, the ultrasonic held transmitted in wate r and measured by the same optical probe is compared with simulations based on the diffraction impulse theory, The results of that compariso n deafly show that, as far as diffraction is concerned, a piezocomposi te transducer behaves like a homogeneous material.