Possibility of cw lasing on self-terminating transitions of metal atoms

The possibility of achieving cw lasing on self-terminating transitions of metal atoms is examined theoretically for the case in which the lower working level is one of a group of metastable levels which are effectively mixed in collisions with atoms and molecules of a buffer (quenching) gas. The presence of the group of metastable levels has two consequences. First, it substantially raises the efficiency of the depopulation of the lower working level by heavy particles. Second, it creates conditions such that electrons cause a relaxation of this group of levels to the ground state. As a result, the quenching-gas pressure required for cw lasing is reduced to ~10 torr. The ranges of gas temperatures in which cw lasing can be achieved in this scheme are estimated. It is suggested that organometallic compounds be used as the active media in these lasers.