Subterahertz Acoustic Solitons under Second-Harmonic Generation Conditions

The pulsed regime of second acoustic harmonic generation in the subterahertz range in a paramagnetic crystal has been analytically studied. An exact solution of the corresponding nonlinear wave equations for slowly varying amplitudes as a two-color soliton has been obtained in the absence of phase and group matching and at zero group velocity dispersion parameter at the second harmonic frequency. The soliton has been shown to be formed at a relative proximity of the carrier frequency of the input pulse to the spectral line of the quantum transition between the Zeeman sublevels of impurity paramagnetic ions.