Ternary tellurite glasses were prepared by a conventional quenching method in the system TeO
2-LiO
0.5-YO
1.5⋅IR spectra reveal that the glasses contain the following polyhedra: deformed TeO
6 groups, TeO
4-trigonal bipyramids, TeO
3-trigonal pyramids, or combinations of these polyhedra. The highly addition of glass-network modifiers, especially Li
+ ion, leads to a collapse of polyhedra networks. The intense emission peak, due to the transition
4S
3/2-
4I
15/2' was found at 546 nm in tellurite glasses doped with Er
3+ under 378 nm and 973 nm excitations at the room temperature. Upon excitation at 973nm, the emission shows a typical upconversion characteristic, indicating the quadratic profiles of the emission intensities against the exciting powers. The emission intensities tend to be dependent upon 378nm excitation, but independent of Er
3+ concentration upon 973 nm excitation. The excitation and emission involve two photons process through the
4I
11/2 level of Er
3+ ion. Up conversion fluorescence is, also, enhanced at 547nm by the supplementary doping with Yb
3+ ion.
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