Role of atomic coherence in the propagation of two-color lasers in an autoionizing medium

We study the role of atomic coherence in the propagation dynamics of two-color lasers in an autoionizing medium. By solving the coupled equations for atoms and fields simultaneously, it is found that the asymptotic value of the phase difference after a long propagation distance critically depends on the detuning from an autoionizing resonance and the asymmetry parameter, suggesting that inherent atomic coherence of an autoionizing system, which is absent in a bound state system, plays an important role during the propagation processes. Our numerical findings are consistent with our theoretical analysis using a series expansion method of the coupled equations.