Visualization of surface displacement and transmitted field of piezocomposite transducers by optical probing

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 μm pitch piezocomposite are probed with an 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 behaviour. 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 an homogeneous material