The Co:MgF
2laser, tunable over the range from 1.5 to 2.3 μm, has been investigated under a variety of operating conditions. Included in this paper are reports on basic spectroscopy of Co:MgF
2, a determination of the gain cross section, the efficiency and temporal behavior under pulsed excitation, and performance in the

-switched mode. In addition, operation with thermoelectric cooling and CW oscillation at the multiwatt power level are discussed. Equations covering laser-pumped lasers are derived and comparisons between experiments and theory are presented.