Electromagnetically induced absorption in Rb atoms with circular polarization of laser beams: Effects of neighboring transitions.

We have studied the effects of neighboring transitions on electromagnetically induced absorption (EIA) and electromagnetically induced transparency (EIT) in the D2 transition line in Rb atoms with respect to the same circular polarization configurations ( ) of coupling and probe lasers. Spectra for the open transition of Rb and the and 3 transitions of Rb exhibit EIA, resulting from the neighboring effect of and transitions, respectively. In contrast, EIT is observed for the open transition of Rb, which indicates greater hyperfine energy splittings of Rb and weaker neighboring effects than those of Rb. Based on the theoretical results, we can confirm that EIT in the case of for Rb for the same circular polarization configuration transforms into EIA due to the magnitude of the neighboring effects with a decrease in the hyperfine energy splittings.