Splitting of electromagnetically induced transparency window and appearing of gain due to radio frequency field

Two resonant radio frequency fields are added to lambda three-level system in this paper. By discussing the behaviors of probing field absorption profiles under the effect of different Rabi frequencies of two radio frequency fields, the splitting of electromagnetically induced transparency (EIT) can be seen and the overlapping between EIT and gain can be obtained. The results show that the two radio frequency fields have different control functions on the system. The radio frequency field which interacts with hyperfine levels of ground state plays a role in the splitting of EIT, but the radio frequency field which interacts with hyperfine levels of excited state does not work on it. In addition only when the Rabi frequency of radio frequency field interacting with hyperfine levels of ground state is greater than with hyperfine levels of excited state, can the new features about the overlapping between EIT and gain be obtained.