Absorption and emission spectral analysis of Pr: tellurite glasses

This paper reports on the results concerning optical absorption and fluorescence properties of 60TeO2-25ZnO-10BaO-4.5La2O3-0.5Pr2O3 (Pr: TZBL) glass. Both electronic (alphae) and vibrational (alphav) band edge cut-off wavelengths of the host glass (TZBL) have been evaluated from the measurement of its UV-Vis and IR transmission spectra. The glass studied has shown 80% transmittance throughout its optical window from 0.366 mum (alphae = 3.39 eV) to 6.30 mum (alphav = 0.197 eV). The FT-IR transmission spectra of Pr doped and also reference tellurite glasses have demonstrated the presence of TeO4 and TeO3+1 or TeO3 structural units. The thermal properties of this glass have been investigated from the study of DTA profile. The recorded optical absorption spectra of Pr: TZBL glass have shown eight absorption bands from 300 nm to 2,500 nm. The fluorescence emission has been observed mainly from P1, P0 and D2 states to the lower lying states and which are assigned to the transitions of P0- > H4,5,6; P0- > F2,3,4; P1- > H5 & D2- > H4,5 upon excitations at three excitation states of P0,1,2. From the time resolved spectra, it is found that P0 level decays faster than D2 level. The fluorescence decay kinetics of P0 and D2 levels have been measured and the lifetimes are found to be 21 and 39 mus, respectively.