Pulsed Fe2+:ZnS laser continuously tunable in the wavelength range of 3.49 — 4.65 μm

A laser based on a Fe²⁺:ZnS crystal is demonstrated for the first time. Lasing in this crystal is obtained at room temperature under pumping by 40-ns pulses of an Er:YAG laser at a wavelength of 2.94 nm. The slope efficiency of the Fe²⁺:ZnS laser with respect to the absorbed pump energy was 32%, and the output energy reached 3.4 mJ. Continuous tuning of the laser wavelength within the range of 3.49 — 4.65 nm was achieved using an intracavity dispersion prism.