NONLINEAR REFLECTION OF SURFACE-WAVES AT A CONTACT INTERFACE BETWEEN 2 SOLIDS

The nonlinear reflection of surface acoustic waves from a contact interface between solids is observed experimentally. It is shown that the spectrum of the reflected wave is transformed as a result of the efficient generation of higher surface wave harmonics in the backward direction from the contact zone. Inversion of the spectrum of a nonlinearly reflected wave is observed under the conditions of weak linear reflection (at an interface between media with similar linear properties). This effect can serve as a general identifying characteristic of nonlinear sound reflection processes.