Lasing characteristics of heavily doped single-crystal Fe:ZnSe

Characteristics of a Fe: ZnSe laser are studied at room temperature. The laser active elements are heavily doped single crystals with the Fe2+ ion concentration n = 0.64 x 10(19) - 5.7 x 10(19)cm(-3), grown from melt by the Bridgman method. The generated energy of 870 mJ is obtained at the total efficiencies with respect to the absorbed and incident energies eta(abs) = 43% and eta(inc) approximate to 35%, respectively. The laser slope efficiency with respect to the absorbed energy is eta(slope) approximate to 50%. In a heavily doped active element with the Fe2+ concentration n = 5.7 x 10(19)cm(-3), in which the medium excitation depth is just a part of the total element dimension along the optical axis ( the element is completely non-transparent for the pumping radiation), the radiation spectrum of the Fe:ZnSe laser shifts to the long-wavelength range by more than 300 nm as compared to spectra of the laser on crystals excited along the whole element length. It is shown that Fe:ZnSe lasers on heavily doped single-crystal elements can be efficiently excited by a radiation of a Cr:ZnSe laser without tuning the spectrum of the latter to the longer wavelength range.