Coherent transfer of population in an atomic system in the presence of buffer gas

We consider an atomic dual Λ-system under two-laser-field excitation to investigate the possibility of indirect coherent transfer of population between atomic ground states through an excited state. The atomic system, namely atomic vapor in a buffered cell, is excited by a frequency modulated pump laser and probed by a low-power cw laser. The study can be helpful to understand the mechanisms of collisional coherent transfer of population and other related phenomena and applications.