Growth and spectroscopic properties for Ho3+:SrGdGa3O7 crystal

Abstract The Ho 3+ :SrGdGa 3 O 7 single crystal was grown by the Czochralski method. The polarized absorption spectra, emission spectra and fluorescence decay curve of the crystal were measured at room temperature. The absorption cross-sections, corresponding to 5 I 8 → 5 G 6 + 5 F 1 absorption bands, are 4.4 × 10 −20 cm 2 for π polarization and 3.5 × 10 −20 cm 2 for σ polarization. Based on the Judd–Ofelt theory and the polarized absorption spectra, the spontaneous transition probabilities, the fluorescent branching ratios and the radiative lifetimes were calculated. The crystal exhibited a broad emission band from 1900 nm to 2100 nm and the stimulated emission cross-section at 1990 nm is 1.01 × 10 −21 cm 2 . The fluorescence lifetime of 5 I 7 multiplet of Ho 3+ ions is up to 9.17 ms. The results show that the Ho 3+ :SrGdGa 3 O 7 crystal is a promising gain medium for tunable and ultrashort pulse lasers operating around 2.0 μm.