Electromagnetically induced transparency and Autler-Towns effect in multi-level cascade type system in 133Cs

Abstract

The probe field propagation through a twelve-level Ξ type atomic system, having two ground energy levels, four intermediate energy levels and six upper energy levels, is studied theoretically in presence of a control field connected from intermediate energy levels to upper energy levels of the transitions of 133Cs atom. Optical Bloch equations (OBEs) for the system are derived by density matrix formalism and are solved numerically under Doppler free and Doppler broadened conditions. The control field can simultaneously remain resonant or nearly resonant with certain hyperfine transitions and highly detuned with respect to other transitions. Under Doppler free condition the probe absorption curve shows multiple electromagnetically induced transparency peaks (EIT) formed within largely separated Autler-Towns (A-T) peaks. The A-T peaks are formed due to the dressing of the hyperfine transitions coupled by a highly detuned control field. The EIT windows get widened with increase in the Rabi frequency of the control field. The numerical result is compared with analytically solved reduced three-level Ξ type system. At room temperature the multiple transparency peaks get masked due to thermal averaging and an overall transparency like feature appears in the simulated Doppler broadened probe absorption curve.