Dynamics of energy transfer and frequency upconversion in Tm3+ doped fluoroindate glass

Blue and ultraviolet upconversion (UC) emissions at 455 and 363 nm were observed from Tm3+ doped fluoroindate glasses pumped at 650 nm. The time behavior of the UC signals was studied for different Tm3+ concentrations. The measurements revealed the origin of the UC process as well as allowed to quantify the interaction between Tm3+ ions. The results indicate that a two-step one-photon absorption process is responsible for the UC emissions, and dipole-dipole interaction provides the main contribution for energy transfer (ET) among active ions. The critical distance between Tm3+ ions at which the ET rate is equal to the decay rate of noninteracting Tm3+ ions was determined. (C) 2004 American Institute of Physics.