Impact of codopant ions on 2.5-3.0 µm emission of Er3+:4I11/2→4I13/2 transition in Yb,Er,Eu:LaYSGG crystal

- Yb,Er,Eu:LaYSGG crystal was obtained by the Czochralski technique for the first time.
- Enhanced 2.5-3.0 µm emission was observed in Yb,Er,Eu:LaYSGG crystal as compared with Er:YSGG crystal, owing to the codopant Yb3+ and Eu3+ ions.
- The energy transfer efficiencies of Yb3+→Er3+ (ET1) and Er3+→Eu3+ (ET2) were estimated to be 94.8% and 93.9%, respectively.
- Yb,Er,Eu:LaYSGG crystal is proved to be an excellent candidate of LD pumped 2.5-3.0 µm laser gain medium.

The crystal of 1 at% Yb3+, 10 at% Er3+ and 0.1 at% Eu3+ triply doped La0.3Y2.7Sc2Ga3O12 (abbr. as Yb,Er,Eu:LaYSGG) was grown for the first time by using a Czochralski technique. Its absorption, near-infrared and mid-infrared fluorescence spectra, as well as the fluorescence decay curves of Er:4I13/2 and 4I11/2 levels were measured at room temperature. The spectroscopic properties including the absorption and emission cross-sections as well as the fluorescence lifetimes of the title crystal were revealed and compared with 10 at% Er3+:Y3Sc2Ga3O12 crystal. Spectral analyses show that the sensitization of Yb3+ ion leads to an enhanced 2.5-3.0 µm emission corresponding to Er3+:4I11/2→4I13/2 transition in the grown crystal, meanwhile, the depopulation of Eu3+ ion from Er3+ inhibits the self-termination effect successfully. The energy transfer mechanism was discussed; the energy transfer efficiencies of Yb3+→Er3+ (ET1) and Er3+→Eu3+ (ET2) were estimated to be 94.8% and 93.9%, respectively. The results indicates that Yb,Er,Eu:LaYSGG crystal is a good candidate for LD pumped mid-infrared laser.