Absorption and emission spectral analysis of Pr3+: tellurite glasses

This paper reports on the results concerning optical absorption and fluorescence properties of 60TeO(2)-25ZnO-10BaO-4.5La(2)O(3)-0.5Pr(2)O(3) (Pr3+: TZBL) glass. Both electronic (alpha(e)) and vibrational (alpha(v)) 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 mu m (alpha(e) = 3.39 eV) to 6.30 mu m (alpha(v) = 0.197 eV). The FT-IR transmission spectra of Pr3+ 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 Pr3+: TZBL glass have shown eight absorption bands from 300 nm to 2,500 nm. The fluorescence emission has been observed mainly from P-3(1), P-3(0) and D-1(2) states to the lower lying states and which are assigned to the transitions of P-3(0) -> 3H(4,5,6); P-3(0) -> F-3(2,3,4); P-3(1) -> H-3(5) & D-1(2) -> H-3(4,5) upon excitations at three excitation states of P-3(0,1,2). From the time resolved spectra, it is found that P-3(0) level decays faster than D-1(2) level. The fluorescence decay kinetics of P-3(0) and D-1(2) levels have been measured and the lifetimes are found to be 21 and 39 mu s, respectively