Enhanced ~2.7 µm emission investigation of Er3+:4I11/2→4I13/2 transition in Yb,Er,Pr:SrLaGa3O7 crystal

Abstract

The bulk crystal of 5at% Yb3+, 20at% Er3+ and 0.2at% Pr3+ triply doped SrLaGa3O7 (abbr. as Yb,Er,Pr:SLGO) was grown by the Czochralski method. The effects of co-dopant Yb3+ and Pr3+ on the spectroscopic properties and the mutual energy transfer mechanism were investigated, via the measurements of its absorption, near-infrared and mid-infrared fluorescence spectra, as well as the fluorescence decay curves of Er3+:4I13/2 and 4I11/2 levels at room temperature. As compared with 20at% Er3+ singly doped SrLaGa3O7 crystal, ~2.7µm emission intensity corresponding to Er3+:4I11/2→4I13/2 transition is enhanced greatly in the Yb,Er,Pr:SLGO crystal. Spectral analyses indicate that the sensitization of Yb3+ to Er3+ improves the ~2.7µm emission in Yb,Er,Pr:SLGO crystal, meanwhile, the depopulation of Pr3+ from Er3+ decreases the ~1.5µm emission and inhibits the self-termination effect. The energy transfer efficiencies of Yb3+→Er3+ (ET1), Er3+→Pr3+ (ET2) and Er3+→Pr3+ (ET3) were estimated and discussed. The above results conclude that Yb,Er,Pr:SLGO crystal is a good candidate for LD pumped mid-infrared laser.