Role of different type of sub-systems in doubly driven Lambda-system in 87Rb

The well known Lambda-system using two ground state hyperfine levels, F=1 and F=2 of 5S1/2 and one hyperfine level, F=2 of excited state of 5P3/2 of 87Rb has been recently studied using two counter- propagating control lasers [1]. The experiment shows conversion of electromagnetically induced transparency (EIT) into electromagnetically induced absorption (EIA) because the doubly driven Lambda-system forms various sub-systems. We here present detailed theoretical study of the different possible sub-systems created by this configuration. We also explore the possibility of tuning the strength of individual sub-systems by changing the polarization of the control lasers.