The mechanism of cross-relaxation in Y3Al5O12: Tb3+

Abstract The 5 D 3 − 5 D 3 cross-relaxation of YAG:Tb3+ has investigated by analysis of the 5D3 decay curve as a function of Tb3+ concentration. This technique is a more sensitive test of the mechanism than relative intensity measurements alone. It is shown that the relaxation is predominantly dipole-dipole in character (R0 ∼ 1.3nm), and insensitive to temperature. The population of the 5D4 state following high energy excitation occurs almost entirely via cross-relaxation from the 5D3 state.