Analyses of energy transfer of Cr³⁺ and Nd³⁺ co-doped Y₃Al₅O₁₂ ceramic powders at the ⁴ T ₁ level of Cr³⁺ ion excitation

Abstract

The concentration dependence of energy transfer from Cr3+ to Nd3+ at the 4T1 level excitation in Nd/Cr:YAG was investigated by the fluorescence decay curves of Cr3+ and Nd3+ for Nd/Cr:YAG and Cr:YAG ceramic powders in the Cr3+ concentration range of 0.1 to 6.0 mol%. The energy transfer process between Cr3+ and Nd3+ at the 4T1 level excitation is tried to explain using a rate equation that assumes energy transfer from the 2E–4T2 level to Nd3+ on the basis of dipole–dipole interactions, the same as the 4T2 level excitation. In conclusion, the energy excited to the 4T1 level will relax non-radiatively to the 2E–4T2 level and then transfer to Nd3+. It is presumed there will be no direct transfer from the 4T1 level to Nd3+. Our rate equations will be useful when simultaneously exciting the 4T1 and 4T2 levels of Cr3+ in Nd/Cr:YAG using broadband pumping sources.