Growth and spectroscopic properties for Ho3+:SrGdGa3O7 crystal

Abstract

The Ho3+:SrGdGa3O7 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 5I8→5G6+5F1 absorption bands, are 4.4×10−20cm2 for π polarization and 3.5×10−20cm2 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 1900nm to 2100nm and the stimulated emission cross-section at 1990nm is 1.01×10−21cm2. The fluorescence lifetime of 5I7 multiplet of Ho3+ ions is up to 9.17ms. The results show that the Ho3+:SrGdGa3O7 crystal is a promising gain medium for tunable and ultrashort pulse lasers operating around 2.0μm.