Analytical solutions for a doubly driven two-level atom

We have deduced analytical solutions of an energy level diagram of the doubly driven/dressed atom for a two-level atom exposed to a strong near-resonant bichromatic laser field in a special case, i.e., the bichromatic field with frequencies ω₁ and ω₂, and Rabi frequencies Ω₁ and Ω₂, in which the first coupling field of \varOmega₁ acts on the bare atomic levels, and then the resulting singly dressed states are driven by the second coupling field of Ω₂, thus resulting in the doubly dressed atom. We have measured the probe absorption spectra of a doubly driven two-level atom. The system consists of 5²S_1/2,F=2 and 5²P_3/2,F'=3 states of ⁸⁷Rb atoms in a magneto-optical trap (MOT) as well as the cooling/trapping beams and an additional coupling field. As for the spectroscopic properties of the doubly driven two-level atom, theoretical analytical solutions are in general agreement with the experimental spectrum as a whole.