Efficient IR Fe:ZnSe laser continuously tunable in the spectral range from 3.77 to 4.40 μm

The lasing characteristics of a Fe:ZnSe single crystal grown from the vapour phase by the free-growth technique using the chemical transport in hydrogen are studied. A Fe²⁺:ZnSe laser cooled to liquid nitrogen temperature and pumped by 2.9364-μm radiation from an Er:YAG laser produces the 130-mJ output energy with a slope efficiency of 40% in terms of the absorbed energy, which corresponds to a quantum efficiency of 55%. The lasing spectrum in a dispersive resonator can be continuously tuned between 3.77 and 4.40 μm.