Temperature dependent upconversion and spectroscopic properties of Nd3+ doped barium bismuth tellurite glasses

This work reports on the spectroscopic properties and temperature dependent NIR to visible upconversion of Nd3+ doped barium bismuth tellurite glasses. Raman spectrum analysis was performed to predict the maximum phonon energy. Spectroscopic parameters (Ω2, Ω4, Ω6 and χ) and radiative properties of certain transitions of Nd3+ ions were calculated by applying Judd-Ofelt (J-O) theory. The concentration dependence of NIR emission and visible upconversion intensities of various levels were discussed. Decrease in the experimental lifetime of Nd3+: 4F3/2 level with increase of Nd3+ ion concentration has also been discussed by analysing decay curves of the NIR emission. The variation of upconversion spectral intensities with respect to sample temperature was studied. Thermal quenching was observed in all the upconversion bands and no anomalous variations were observed in the temperature range 14-300 K.