Lasing characteristics of heavily doped single-crystal Fe:ZnSe

Abstract

Characteristics of a Fe:ZnSe laser are studied at room temperature. The laser active elements are heavily doped single crystals with the $$\\hbox {Fe}^{2+}$$\n ion concentration $$n=0.64\\times 10^{19}-5.7\\times 10^{19}\\hbox {cm}^{-3}$$\n , 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 $$\\eta _{\\mathrm{{abs}}}=43\\%$$\n and $$\\eta _{\\mathrm{{inc}}}\\approx 35\\%$$\n , respectively. The laser slope efficiency with respect to the absorbed energy is $$\\eta _\\mathrm{{slope}}\\approx 50\\%$$\n . In a heavily doped active element with the $$\\hbox {Fe}^{2+}$$\n concentration $$n=5.7\\times 10^{19}\\hbox {cm}^{-3}$$\n , 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.