A broadly tunable continuous-wave Fe:ZnSe laser

We have achieved ≥ 840 mW continuous-wave (CW) output power from iron-doped zinc selenide (Fe:ZnSe).1 The beam quality was measured to be M2 ≤ 1.2. The laser exhibited a slope efficiency of 47% with no thermal roll-off at maximum output power. Various dichroic mirrors and other spectral filters were inserted into the cavity to discretely tune the output of the laser from 3843 nm to 4337 nm. Demonstration of arbitrary discrete tuning shows that, in principle, Fe:ZnSe is capable of efficient continuously-tunable CW lasing over nearly 500 nm of bandwidth.