Sensitization and deactivation effects of Nd³⁺ on the Er³⁺: 27 μm emission in PbF₂ crystal

The effect of Nd3+ co-doping as sensitizer and deactivator to the Er3+ ion for enhancing ~2.7 μm emissions under 808nm LD pump was first studied in the Er/Nd co-doped PbF2 crystal. The Er0.01Nd0.02Pb0.97F2 crystal has been successfully grown by the Bridgman method, and the crystals’ fluorescence emission properties and energy transfer mechanisms of series crystals were investigated. It can be seen that through the Nd3+ ion, the lower energy level of Er3+: 4I13/2 has been depopulated, and the upper energy level of Er3+: 4I11/2 has been populated at the same time. Simultaneously, the energy transfer efficiency from the Er3+: 4I13/2 level to the Nd3+: 4I15/2 level is 84.06%, and from the Nd3+: 4F3/2 level to the Er3+: 4I11/2 level is 55.81%, respectively, which indicate that the Nd3+ ion is an effective deactivator and sensitizer ion for enhancing the ~2.7 μm emission in Er/Nd: PbF2 crystal. These advantages suggest that the Er/Nd: PbF2 crystal may be a potential material for ~2.7 μm mid-infrared lasers under the 808 nm LD pump.