Theory of n-fold time-resolved correlation spectroscopy and its application to resonance fluorescence radiation

Extending the concept of the time-dependent physical spectrum introduced by Eberly and Wodkiewicz (1977) the authors present a formula for the n-fold time-resolved correlation spectrum depending on n time and n frequency arguments. The corresponding measuring device consists of n coupled photodetectors with frequency resolving equipment in front of each. As an application the authors consider the resonance fluorescence radiation of a two-level atom irradiated monochromatically. Under certain conditions the authors derive a simple expression for the n-fold detection probability of photons at time ti (i=1, . . ., n) with frequencies belonging to the central peak or to one of the sidebands of the fluorescence triplet.