Analytical solutions for a doubly driven two-level atom**Project supported by Beijing Natural Science Foundation, China (Grant No. 1164016), the National Natural Science Foundation of China (Grant Nos. 11604334, 61227807, and 61575108), and the Tsinghua Initiative Scientific Research Program, China (Grant No. 2013THZ02-3).

Abstract

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 and , in which the first coupling field of acts on the bare atomic levels, and then the resulting singly dressed states are driven by the second coupling field of , 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 5 and 5 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.