3 J pulsed Fe:ZnS laser tunable from 3.44 to 4.19 μm

We report the laser properties of Fe:ZnS in the temperature range from 85 to 186 K. Under pumping by a pulsed free-running 2.94 μ m Er:YAG laser, a maximum output energy of 3.25 J at 85 K was produced with 27% optical-to-optical efficiency. The output wavelength was observed to tune with temperatures from 3.60 μ m at 85 K to 3.78 μ m at 186 K. As the temperature was increased, the absorbed energy slope efficiency decreased from 42.4% at 85 K down to 2.5% at 183 K. With a CaF 2 prism, the Fe:ZnS laser could be tuned from 3.44 to 4.19 μ m at 85 K.