OBSERVATION OF NONLINEAR ACCOMPANYING ELECTRIC-POTENTIAL WAVE IN PIEZOELECTRIC-CRYSTALS

The theory of three-field acoustic interactions in nonlinear piezoelec tric crystals predicts that the second-harmonic acoustic wave is accom panied by the second-harmonic electrical potential wave due to the ele ctroacoustic nonlinearities of the media. An experiment to demonstrate the phenomenon carried out for crystal LiNbO3 is described in this le tter. Ultrasonic waves excited by a 30 MHz quartz transducer propagate along the z direction of LiNbO3 crystal. The nonlinear electric poten tial wave accompanying with the acoustic wave is directly detected by use of the capacitive detector. To the author's knowledge, this kind o f observation has not been made before. (C) 1994 American Isntitute of Physics.