Growth, defects, radiation resistant and optical properties of 30 at% Er:GSAG laser crystal

30 at% Er³⁺:GSAG single crystal was successfully grown by the Czochralski method. The dislocation of (111) face is studied using the chemical etching with the phosphoric acid etchant. The luminescence properties at 2.6–3.0 µm are systematically studied by measuring the fluorescence spectra and lifetimes to the transition of ⁴I_11/2 → ⁴I_13/2. The long fluorescence lifetime, high fluorescence intensity, and large gain σ_em spectra indicate that the 30 at% Er:GSAG crystal has the great potential for the multi-wavelength laser output at 2.6–3.0 µm. Meanwhile, the absorption and fluorescence properties of 30 at% Er:GSAG crystal under the gamma-ray radiation with three different intensities (35, 70, and 105 Mrad) have been investigated, indicate that this crystal can be considered as a promising MIR laser gain medium for being used under radiant environment. In addition, the luminescence property of 30 at% Er:GSAG crystal in visible and 1.5–1.7 µm was also studied, which shows the possibility to generate the laser around 1.6 µm.