RADIATION AMPLIFICATION NEAR AN AUTOIONIZING STATE

We present an internally consistent theory of amplification near the m inimum of autoionizing states with quantitative application to calcium . We have included a completely specified three-photon pumping and we find certain unusual aspects of the system. We find conditions under w hich the system remains in a steady state, although being coupled to t he continuum. For incoherent pumping we obtain quantitative results fo r the gain. Our results and their extensions are also discussed in the context of present-day experimental possibilities.