Conditional probability densities for photon emission in resonance fluorescence

A two-state atom in a laser beam, near resonance with the atomic transition, emits fluorescent photons. We have obtained the probability density for the emission time of the nth photon, after the emission of an initial photon at time zero. It is shown that the behavior of these probability densities depends strongly on the laser power. For low irradiation, the functions have a single peak with a long tail, but for higher power oscillations are present. The probability density for the first photon has strong oscillations, whereas for subsequent photons the probability density oscillates moderately on a smooth background.

► We consider photon emissions in resonance fluorescence.
► We have obtained the conditional probability densities for photon emission.
► We illustrate the oscillatory nature of the probability densities.