The fluorescence spectrum from a three-level atom in V configuration driven by strong coherent laser fields and the time-dependent squeezing effect in the fluorescence fields with different mixtures of the spectrum lines are investigated analytically.
The dependence of squeezing on the number of atoms is discussed in the time-dependent collective resonance fluorescence of N two-level atoms, coherently driven by a strong resonant laser field. It is shown that, for strong driving field, squeezing appears only in the transient regime of resonance fluorescence. The location of squeezing in time is independent of the number of atoms and the initial atomic populations. It is found that despite the reduction in the amount of squeezing per single atom, squeezing increases in the whole resonance fluorescence field as the number of atoms increases, and attains its maximal value for moderate N. Moreover, the maximal value of squeezing is dependent on the intensity of the driving field. As the latter increases, the maximum of squeezing increases and shifts towards larger numbers of atoms. For a very large number of atoms, however, squeezing is altogether removed.
Time-dependent features of the fluorescence radiation from a strongly driven three-level atom in a Raman configuration are studied applying the Eberly-W\'odkiewicz counting-rate definition of the spectrum. Using our earlier formalism, where we assume that one or both of the driving fields are intense, we obtain analytical expressions for the time-dependent fluorescence spectra. We have also studied the influence on the transient spectrum of the initial preparation of the atom in three different dressed states.