Propagation of generalized multi-Gaussian correlated Schell-model beams in electromagnetically induced transparency atomic vapor

Propagation of generalized multi-Gaussian correlated Schell-model (GMGCSM) beams through four-level electromagnetically induced transparency (EIT) atomic vapor is investigated for the first time. Analytical expression for the GMGCSM beam passing through an ABCD optical system of EIT vapor is deduced and employed to analyze its propagation properties. It is demonstrated that intensity evolution of the targeted GMGCSM beam through EIT atomic vapor is dependent on the coupling Rabi frequency of the control light, the beam index and coherence length. Moreover, analysis shows that degree of coherence of the beam can also be regulated by the coupling Rabi frequency. Additionally, it is shown that, selecting appropriate coherence length, GMGCSM beams of the first kind would form a shift from a dark-centered distribution known as "optical cage", to a peak-centered distribution; GMGCSM beams of the second kind would shift from a flat-topped distribution to a Gaussian distribution. Therefore, EIT atomic vapor provides a method to regulate the coherence of partially coherent beams. Results obtained here could be expected applications in free-space optical communications, material thermal processing, and optical trapping.