Polarized spectroscopic properties of disordered Er 3+ :Gd 2 SrAl 2 O 7 crystal

A multi-position disordered Er 3+ :Gd 2 SrAl 2 O 7 single crystal was grown by the Czochralski method. Room temperature polarized spectral properties of the crystal were investigated in detail. The Judd–Ofelt theory was applied to analyze the polarized absorption spectra. The peak stimulated emission cross-sections of the 4 I 13/2 → 4 I 15/2 transition reach 0.79 ×10 −20 and 1.25×10 −20 cm 2 for σ and π polarizations, respectively. The gain curves are flat with full widths at half the maximum larger than 60 nm. Fluorescence lifetimes of the 4 I 13/2 multiplet for Er 3+ ions were fitted to be 4.93 ms and 3.48 ms from measured fluorescence decay curves for bulk and powder samples, respectively. The results show that the Er 3+ :Gd 2 SrAl 2 O 7 crystal may be a potential gain medium for a 1.55 µm laser with low pumping threshold.