ENERGY-TRANSFER UP-CONVERSION IN GD3GA5O12PR3+

Excitation of Pr3+-doped Gd3Ga5O12 crystals at 580 nm (1D2 <-- H-3(4)) produces fluorescence at 486 nm (P-3(0) --> H-3(4)) which is attribut ed to upconversion from interacting Pr3+ ions. Based on an analysis of the lifetimes of the levels P-3(0), 1D2 and the induced fluorescence (P-3(0) --> H-3(4)) we conclude that the mechanism responsible for the upconversion process is energy transfer. This mechanism arises from e xcitation annihilation involving pairs of ions in the H-3(6) and 1D2 l evels.