Spectral properties of a Ξ-configuration atom driven by a pair of bichromatic fields

The absorption spectrum and the incoherent fluorescence spectrum of the lower transition in an Ξ-configuration three-level atomic system driven by a pair of bichromatic fields are investigated. The transmission of absorption profile from multipeaked feature to a single-peak feature is identified. Adjusting the relative phase between the two driving fields, the splitting effects of the spectral peaks occur both in fluorescence and absorption spectra. Furthermore, phase modulating can dramatically lead to a great suppression of the amplitudes of the whole absorption spectrum. Physically, this effect is attributed to the phase-sensitive nature of the populations and coherence between atomic states of the system.