The Rabi frequency in optical spectra

The use of tunable lasers in atomic spectroscopy has provided new opportunities to study the effects of intense coherent resonant radiation on the dynamics of atoms. Under such conditions Rabi oscillations of state probability amplitudes lead to a plethora of new effects in optical spectra such as dynamic Stark splitting of resonances, nutational oscillations in fluorescence and periodic photon bunching and antibunching of the emitted light. We review the extensive developments of effects concerned with the “dressing” of atomic states by intense resonant fields.