Spectroscopic and oscillation properties of Nd3+ and Yb3+ ions optical centers in BaF2-SrF2-CaF2 crystals and ceramics

Spectroscopic properties of Nd³⁺ ions in SrF₂-CaF₂ solid solutions were investigated. The absorption and fluorescence spectra of different individual and clustered optical centers were observed depending on Nd³⁺ ions concentration. The laser properties of SrF₂:Nd³⁺ crystal with neodymium ions concentration of 0.5 at.% containing high symmetry cubic and tetragonal optical centers together with low symmetry clusters were investigated under diode pumping. Using temperature tuning of laser diode pumping wavelength two different lines centered at about 1037 nm and 1044 nm attributed to oscillation of different optical centers were obtained. The slope efficiency of 17% was obtained for short wavelength oscillations at 1037 nm without optimization. The distribution of the output energy between the two oscillating lines for several wavelengths of laser diode pumping. The comparison with LaF₃:Nd³⁺ crystal having single type of Nd³⁺ optical centers was carried out.