Propagation of laser pulse in a three-level cascade inhomogeneously broadened medium under electromagnetically induced transparency conditions

We study a pair of probe and coupling laser pulses propagating in a Doppler broadened three-level cascade atomic medium. Influence of the coupling pulse area on the probe pulse shape is studied in a wide region of pulse duration, from micro to pico second. It is found that the needed value of coupling pulse area to establish an electromagnetically induced transparency (EIT) for the probe light, namely the probe pulse shape is unchanged, is smaller at shorter pulse duration. On the other hand, influence of Doppler broadening is more efficient in the long duration side. These results can find interesting applications in all optical switching, quantum information processing, and transmission.