Dynamic regimes of three-wave interaction of ultrasonic beams in TeO2

Results of experimental and theoretical investigations of dynamic phenomena, which occur under the three-wave resonant interaction of ultrasonic beams in a crystal TeO2, are presented. The interacting waves are fast longitudinal ultrasonic wave (pump, its frequency is 100-1000 MHz) and two slow co- and counter-propagating transverse ones. When the input intensity of the pump wave exceeds similar to5 times the threshold of parametric generation, a complex spatial-temporal dynamics is observed, both regular and chaotic. The resonant three-wave interaction has been simulated by means of solving coupled equations for slowly varying amplitudes of interacting waves, when a transverse inhomogeneity has been taken into account. The spatial-temporal distributions of wave amplitudes within the crystal are complex in all directions and they qualitatively describe the experimental data. (C) 2002 Elsevier Science B.V. All rights reserved.