We report experimental studies of electromagnetically induced transparency in Λ-type and ladder-type atomic systems realized in <sup>87</sup>Rb atoms cooled and confined in a magneto-optical trap. Complete transparency is observed in the Λ-type system with a moderate coupling field. Comparison between the two systems reveals that at the line center of a weak probe transition, destructive interference occurs for the Λ-type system, whereas constructive interference occurs for the ladder-type system. We discuss conditions of complete transparency in the Λ-type system that contains hyperfine magnetic sublevels. Our experimental measurements for the two systems agree with theoretical calculations based on simple three-level Λ-type and ladder-type models.
© 2001 Optical Society of America
Min Yan, Edward G. Rickey, and Yifu Zhu, "Electromagnetically induced transparency in cold rubidium atoms," J. Opt. Soc. Am. B 18, 1057-1062 (2001)