NONLINEAR DETUNING OF 4-WAVE INTERACTIONS

The interaction of four waves propagating in a medium with third-order nonlinearities is considered. In general, nonlinear phase shifts detu ne the interaction before the transfer of energy from the pump to the daughter waves is complete. Fortunately, however, it is possible to co mpensate for this nonlinear detuning by imposing a linear wave-number mismatch on the interaction. Simple criteria are given that allow the weaker pump wave to be depleted completely and, hence, the energy tran sfer to be maximized. Some exact solutions of the four-wave equations are used to illustrate the underlying wave physics, and some useful ap proximate solutions are described. As an application of the general th eory, near-collinear four-wave mixing in a Kerr medium is discussed br iefly.