Probing of Elastic Surface Waves in Piezoelectric Media

Data are presented which indicate that detection of the rf electrical potential associated with an acoustic surface wave in a piezoelectric medium by a simple point probe can yield extensive information about the propagation characteristics of such waves. Such a probe, in mechanical contact with the propagating surface of a 107-MHz LiNbO3 delay line, has been used to measure the diffraction pattern of the acoustic energy, spreading of the acoustic beam, insertion loss due to misalignment of the transducer axis with the crystal symmetry axis, and the amplitude and phase variations of the acoustic wave near the output transducer.