Intrinsic defect related photoluminescence in TeO2- based glasses

Intrinsic defects are an important contributor to the disordered structure of the amorphous state and they govern many of its optical and electrical properties. Intrinsic luminescence (IL) was reported in chalcogenide glasses ([1, 2] and references therein) and in SiO2 based glasses. It was ascribed to intrinsic defects, such as broken bonds in chalcogenide [2, 3] and oxygen deficient centres in silicate glasses (see, e.g., review [4]). In this paper we report on the broad red IL in tellurite (TeO2)(ZnO)(Na2O) glasses. This IL shows a fatigue, it is essentially non-linear with pump intensity contrary to linear Raman scattering. The peak wavelength of this IL shifts to the red and its intensity increases with red shifting of the electronic absorption edge. The edge, in its turn, shifts to the red with increase of the glass melting temperature for the same nominal batch composition. We detected similar IL in tellurite glasses modified with other metal oxides, such as Nb2O5,Li2O, BaO. We discuss the origin of the IL of tellurite glass based on intrinsic defects related to the oxygen vacancy. Due to its large breadth, this IL may find an application in tuneable vibronic lasers. However, we argue that these defects may deteriorate the performance of the Er3+-doped tellurite fibre amplifier, which has been demonstrated to operate in the broadest, to date, wavelength range in the 1.54 um telecommunication window [5]. As the IL is a measure of the number of intrinsic defects, its study will aid evaluation of tellurite hosts for application in telecommunications.