Second-order nonlinear mixing processes involving a leaky guided acoustic wave.

Quasi-phasematched mixing processes of acoustic waves via second-order nonlinearity are analyzed with two perfectly guided waves generating a leaky wave. The efficiency of such processes is quantified by an acoustic nonlinearity parameter (ANP), defined as the linear growth rate of the leaky wave's amplitude in the initial stage of its spatial evolution. Two approximate ways of estimating the ANP of such processes are suggested.