(F_2^+)_A centers in additively colored lithium-doped KI and KBr

Abstract
(F2+)A centers can be produced in additively colored KI:Li crystals provided that the material is colored in a nitrogen-free atmosphere. The optical properties of (F2+)A centers in both additively colored KI:Li and KBr:Li are identical with those reported for electron-beam-colored materials. Formation of (F2+)A centers in additively colored KI:Li provides the basis for achieving a stable color-center laser material tunable from 2 to 4 μm.