Spectroscopic analysis and laser parameters of Nd3+ in Ca3Sc2Ge3O12 garnet crystals

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Sc₂Ge₃O₁₂ (CaSGG) single crystals with the garnet structure have been grown by means of the flux growth technique. The doping with Nd³⁺ and Mg²⁺ (as charge compensator) yields samples suitable for optical spectroscopy experiments. The absorption and emission properties have been measured at temperatures ranging from 10 to 298 K. The emission spectra give evidence of the presence of non-equivalent Nd³⁺ sites. The decay time of the 1.06-μm emission band has been measured as a function of temperature and incident power. The intensities of the 298 K absorption transitions have been analyzed by means of the Judd–Ofelt theory. The radiative lifetimes, the branching ratios (β), and the spontaneous emission probabilities have been evaluated for the ⁴F_3/2 excited state using the calculated intensity parameters. The stimulated-emission cross sections and the branching ratios have been estimated from the experimental data for the most important laser transitions indicating that this crystal can be considered an interesting material for solid-state laser applications.