Effect of four-wave mixing on electromagnetically induced transparency in \Lambda-type system with a two-photon probe field

Using density matrix equation, we calculate analytically as well as numerically the effect of the four-wave mixing (FWM) field on electromagnetically induced transparency (EIT) in the rubidium 5S_1/2-5P_3/2-5D_5/2 \Lambda-type system with a two-photon probe field. The calculated results are in good agreement with Fulton's experimental results in 1995 Phys. Rev. A 52 2302.