Upconversion in Pr3+ doped tellurite glass

Optical absorption, luminescence and upconversion (NIR to Visible) in Pr3+ doped tellurite glass at different concentrations of Pr3+ have been studied and several optical properties of the glass have been shown. For upconversion the first NIR photon is absorbed non-resonantly to populate 1G4 level through phonon assisted excitation. The excited Pr3+ ion absorbs another NIR photon and transits upwards to 3PJ levels, which emit fluorescence from 3P2,1,0 and 1D2 to the ground (3H4) and different low-lying excited states. The upconverted luminescence show several transitions including 3P2 → 3H4 not observed in one photon process. Upconversion luminescence does not show significant dependence upon the concentration of Pr3+. This confirms ESA is the most probable channel for upconversion. The temperature dependence of the upconversion luminescence has also been studied. The luminescence quantum efficiency and upconversion efficiency for 3P0 → 3F2 transition for 0.5 mol% of Pr3+ in tellurite glass is found to be ∼3.3% and ∼1.7%, respectively.