Effect of Pulse Shaping on Electromagnetic Induced Transparency and its Applications*

We have theoretically studied the effect of pulse shapes on Electromagnetic Induced Transparency (EIT) and the propagation of pulses inside EIT medium. Our numerical simulations are based on an isotropic homogeneous medium composed of 3-level $\Lambda $ type atoms coupled to two co-propagating laser fields. It has been found that even with the two-photon resonance, if these two fields have unmatched pulse shapes, there is still no EIT. The mechanism is explained in the dressed state, in which a pulse shape dependent interaction is found. We also observed the nonlinear effect of EIT on pulse propagation inside medium by using Fourier Analysis. Some possible applications are proposed.