Population inversion and absorption spectrum of a V-type three-level atom driven by coherent and stochastic fields

摘要

The steady-state populations and the absorption spectrum of a V-type three-level atom driven by a strong coherent field and a weak stochastic one simultaneously are investigated. The population inversion in bare-state and dressed-state bases can happen significantly due to the effect of the stochastic field. A relation between the level gap of both atomic excited states and the Rabi frequency is found to decide in which excited state the population is larger than in another one for the same frequency detuning delta between the coherent and the stochastic fields. The line profiles of the absorption spectrum are strongly dependent on the frequency detuning 6. Different lineshapes such as a sharp emission peak (gain), an absorption peak or a dispersion-like peak can be exhibited at the line centre for different delta. Asymmetrical spectral features and line narrowing can be reached by adjusting 6 and the Rabi frequency. Probe gain in sidebands can occur due to the unbalanced population distribution in dressed states. [References: 28]