Fully resonant three-wave mixing in isotropic media under induced transparency conditions

A theoretical investigation is reported of three-wave frequency mixing under simultaneous single-photon and two-photon resonance conditions when one of the fields being mixed is weak and the other is strong. A study is made of the influence of the field splitting on the nonlinear susceptibility in the case of homogeneously and Doppler-broadened transitions. An analysis is made of the role played by interference between quantum transitions via quasilevels in absorption and generation, and of its influence on mixing. It is shown that significant enhancement of the nonlinear generation efficiency is possible in optically dense media.