LAUSR

Abstract The bulk crystal of 5at% Yb 3+ , 20 at% Er 3+ and 0.2 at% Pr 3+ triply doped SrLaGa 3 O 7 (abbr. as Yb,Er,Pr:SLGO) was grown by the Czochralski method. The effects of co-dopant Yb 3+ and Pr 3+ 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 Er 3+ : 4 I 13/2 and 4 I 11/2 levels at room temperature. As compared with 20at% Er 3+ singly doped SrLaGa 3 O 7 crystal, ~2.7 µm emission intensity corresponding to Er 3+ : 4 I 11/2 → 4 I 13/2 transition is enhanced greatly in the Yb,Er,Pr:SLGO crystal. Spectral analyses indicate that the sensitization of Yb 3+ to Er 3+ improves the ~2.7 µm emission in Yb,Er,Pr:SLGO crystal, meanwhile, the depopulation of Pr 3+ from Er 3+ decreases the ~1.5 µm emission and inhibits the self-termination effect. The energy transfer efficiencies of Yb 3+ →Er 3+ (ET1), Er 3+ →Pr 3+ (ET2) and Er 3+ →Pr 3+ (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.