Energy transfer in YAlG:Nd codoped with Ce

Laser excited luminescence has been used to study an energy transfer between Ce³⁺ and Nd³⁺ ions in YAlG:Nd,Ce laser crystal with varying small Ce concentrations. Radiative Ce³⁺→Nd³⁺ energy transfer dominates in the studied single crystal samples but this process can also be accompanied by multistep transfer mechanisms (for example by (Ce³⁺→Ce³⁺)_n→ Nd³⁺ transfer mechanism). The Ce³⁺→Nd³⁺ radiative energy transfer improves pumping of green and yellow excitation lines in YAlG:Nd,Ce laser rods because the contribution of the additional transfer pumping of Nd³⁺ ions from Ce³⁺ ions is more than three times greater than should be expected from concentration differences between Nd and Ce. This favourable behaviour is explained from high quantum efficiency of Ce³⁺ emission and higher Ce³⁺ absorption cross sections in comparison with the Nd³⁺ ones (more than one order of magnitude difference).