Study on the ac-Stark splitting in a four-level system
四能级系统中ac-Stark分裂研究

We present a model of the four level system driven by double optical fields and investigate the resonant fluorescence spectroscopy in detail. The ac Stark splitting exhibits in the resonant fluorescence spectroscopy from an upper level to lower-lying levels, which occurs over a wide range of the parameters. The ac Stark splitting does not occur when only exists a coherence field. For certain Rabi frequencies, there are double dark lines in the four level system. The generation of ac Stark splitting is the result of the multi channel quantum interference. The origin of the ac\|Stark splitting is explained clearly by the theory of dressed state.