Enhanced 2.75 μm emissions of Er3+ via Eu3+ deactivation in PbF2 crystal

The use of Eu3+ codoped for the enhancement of the transition of Er3+:I-4(11/2) -> I-4(13/2) similar to 2.75 mu m emissions was observed in the Er/Eu co-doped PbF2 crystal for the first time. The similar to 2.75 mu m energy transfer mechanism and fluorescence emission properties of the Eu/Er co-doped PbF2 crystal were investigated at length. The results show that the codoped of Eu3+ ion in Er/Eu:PbF2 crystal greatly enhances Er3+:2.75 mu m emission under excitation of a common 970 nm laser diode. In addition, it is found that the Eu3+ ion depopulates the lower laser level of Er3+:I-4(13/2), and has little effect on the upper laser level of Er3+:I-4(11/2) at the same time. Moreover, the energy transfer efficiency from the Er3+:I-4(13/2) level to the Eu3+:F-7(6) level is as high as 88.07%, indicating that the Eu3+ ion is an effective deactivation ion for enhancing the similar to 2.75 mu m emission in Er/Eu:PbF2 crystal. These advantageous spectroscopic characteristics suggest that the Er/Eu:PbF2 crystal may be a promising material for similar to 2.75 mu m mid-infrared lasers under the pump of a conventional 970 nm LD.