Two-color interference effect involving three-photon excitation and four-wave-mixing processes

We have extended observations of total cancellation of three-photon atomic excitation by internally generated fields due to four-wave mixing. The process was found to occur as predicted in an excitation mode involving two photons of frequency ${\omega }_1$ and one of frequency ${\omega }_2$, plus the generated four-wave-mixing field at frequency 2${\omega }_1$+${\omega }_2$. Experiments were conducted on the 6s state of Xe.