Transient four-wave-mixing line shapes: Effects of excitation-induced dephasing

We describe the transient four-wave-mixing (FWM) response in systems where decay of the optically induced coherence depends on the excitation level of the system. Using modified optical Bloch equations, we show that excitation-induced dephasing due to phase-interrupting excited-state interactions qualitatively modifies the temporal behavior and polarization dependence of the FWM signal.