Energy and spectral–temporal characteristics of a Fe:ZnSe laser on heavily doped single crystals

Energy and spectral–temporal characteristics of lasers on heavily doped single crystals Fe:ZnSe are studied. With the cavity formed by faces of the crystal at a bivalent iron concentration of 2.8 × 1019 cm−3, the slope and total laser efficiencies with respect to the absorbed energy were 53% and ≈ 42%, respectively. Laser spectra with the cavity free of air and elements capable of forming Fabry–Perot interferometers were recorded using a monochromator with an HPL-256-500 (HEIMANN Sensor) pyroelectric line photodetector. The spectra have a periodical structure with the period of about ≈ 4 cm−1. A similar periodical structure was observed in other cavity types with active elements differing in thickness, production technology, and even crystal material (Fe:ZnSe, Fe:ZnS). Presently, we have no adequate explanation for such a periodical structure. A simple method is suggested for obtaining nanosecond radiation pulses in the spectral range of 4–5 µm based on heavily doped Fe:ZnSe single crystals.