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

Blue and ultraviolet upconversion (UC) emissions at 455 and 363 nm w ere observed from Tm3+ doped fluoroindate glasses pumped with a 650 nm pulsed dye laser. The temporal behavior of the fluorescence signal originate from the D-1(2) manifolds was studied for different Tm3+ concentrations. The fluorescence 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 absorption process is responsible for the UC emission and the dominant interaction contributing for ET among of active ions is the dipole-dipole interaction.