Upconversion due to energy transfer involving Pr3+ ions in pairs

Upconversion luminescence in triply ionized praseodymium-doped TeO2-Li2O glass using excitation at similar to 590 nm into the D-1(2) level from a dye laser pumped with the second harmonic of a pulsed Nd:YAG laser has been reported. The mechanism involved in the upconversion emission observed at similar to 480 nm indicates that the most important contribution is energy transfer among praseodymium ions in pairs followed by the dipole-dipole interaction. The rate-equation model for the emission at similar to 480 nm that provides direct information to determine the energy-transfer rates containing the pair of states involved in the upconversion process has been explored.