OBSERVATION OF A NEW CLASS OF CRYSTAL SONOLUMINESCENCE AT PIEZOELECTRIC CRYSTAL-SURFACE

Ultrasonic vibrations of a single-piezoelectric crystal of LiNbO3 and CdS can excite luminescence of gas near the crystal surface. Light exc itation starts at ultrasonic intensity above a certain threshold. This threshold lies in the range 3-10 W/cm(2) and corresponds to the unpin ning of dislocations and beginning of their reversible motion in the; piezoelectric crystal. The effects constitute a new class of acousto-o ptic and dislocation phenomena having the main feature of energy trans formation from ultrasound in solid to luminescence of gas at normal at mospheric pressure. The unpinning of dislocations is shown to be criti cal for sonoluminescence excitation. (C) 1997 American Institute of Ph ysics.