Electron collisional laser in Pb+ populated by recombination

A quasi-steady-state inversion and laser action in the near infrared in Pb+ are shown to occur as a consequence of recombination and subsequent electron collisional thermalization within two ’’bands’’ of atomic energy levels. This demonstrates a mechanism for producing similar inversions at short wavelengths in a recombining plasma where the plasma density may be too high for radiative decay to establish an inversion.