Analysis of sub-Doppler linewidths in inversionless amplification

Abstract

In a recent experiment Zhu and Lin [Phys. Rev. A 53, 1767 (1996)] reported gain linewidths, in a coherently pumped atomic system, which were much less than the Doppler width. We show that this observation is easily explained in terms of our work [Phys. Rev. A 53, 2842 (1996)], which is generalized to correspond to the experimental situation by inclusion of incoherent pumping, and pump and probe laser linewidths.