Abstract

In describing four-wave mixing in gases¹ it is useful to distinguish three different intensity regimes: small signal limit; onset of saturation; and high intensity saturation. For optimum conditions one should stay in the regime of the onset of saturation where field-dependent changes of the refractive index start to destroy the phase matching condition. In going to shorter wavelengths a number of competing processes have to be considered: sum frequency mixing, such as difference frequency mixing; two-photon absorption; stimulated emission and parametric processes; redistribution of population densities; and field-dependent changes of the refractive index.

© 1986 Optical Society of America