Theory of resonance fluorescence excited by modulated or pulsed light

TLDR

Resonance fluorescence from atoms with Zeeman or hyperfine structure is expected to change when the exciting light intensity is modulated or pulsed. The study extends an earlier theory of resonance fluorescence to account for variations in the exciting light intensity. Resonance effects arise when the modulation frequency matches a characteristic atomic frequency. In a studied case, pulsed excitation predicts that the fluorescent light will be modulated and damped at the usual spontaneous emission rate.

Abstract

When resonance fluorescence is excited in atoms whose excited states have Zeeman or hyperfine structure, it is to be expected that the character of the fluorescent light will be affected if the intensity of the exiciting light is modulated or pulsed. An earlier theory of resonance fluorescence is developed to take account of such variations of the intensity of the exciting light. Resonance effects are predicted if the light is modulated at a frequency which coincides with a characteristic frequency of the atoms. A particular case, which has been studied experimentally, is worked out in detail. If the exciting light is pulsed, the prediction is that the fluorescent light will be modulated, in addition to being damped at the ordinary rate for spontaneous emission.