Field cross-correlation of time-delayed DFWM signals for population lifetime measurement with incoherent light

Abstract
Two techniques are proposed for measurement of population lifetime with incoherent light, based on the recording of the field cross-correlation between two time-delayed DFWM signals. Theoretical calculations predict that such records exhibit the decay of the population with a resolution given by the coherence time of the light, and against a zero background. An experiment is reported, demonstrating the main theoretical predictions. The features and possibilities of the methods are discussed.