Theoretical and experimental investigations of continuous four-wave mixing
and parametric amplification in a resonantly driven double-Lambda scheme of
Na-2 molecules are reported. Cases of copropagating and counterpropagating
pump waves are analyzed. Macroscopic propagation of the generated fields a
nd the interplay of absorption, Raman gain, four-wave mixing, and parametri
c amplification are studied. (C) 2000 Optical Society of America [S0740-322
4(00)01212-1] OCIS codes: 190.4380, 190.4410, 190.5650, 190.7220.