Stimulated effects in one-photon resonant interferometric four-wave mixing with incoherent light

The interferometric four-wave mixing technique with broadband light is extended to measurements of population relaxation. For what is believed to be the first time, the population relaxation rate in the presence of a pump field is measured. It is shown that stimulated emission can significantly affect the results when one is dealing with resonant transient wave mixing, and, consequently, in most cases stimulated processes should be taken into account.