Abstract
A defect-stabilized F2+ center in NaF with virtually unlimited shelf life at room temperature is described. It has allowed for efficient cw laser action tunable from 1.08 to 1.38 μm. The center is achieved with OH doping and heavy radiation damage. Studies of production of this center and of the similar (F2+)* center in crystals doped with divalent metal ions reveal that in both cases the stabilizing defect is itself a produce of the radiation damage.