The influence of oxides on the optical properties of tellurite glasses

New tellurite glasses within composition 75TeO(2)-5WO(3)-15Nb(2)O(5)-5M(x)O(y) in mol%, where MxOy = (Na2O, Ag2O, ZnO, MgO, CuO, NiO, TiO2, MnO2), have been prepared using the conventional melt-quenching method. The optical properties of these glasses were estimated by measuring the ultraviolet-visible-near infrared (UV-vis-NIR) spectroscopy and linear refractive indices at different wavelengths. From the absorption edge studies, the values of the optical band gap (E-opt) and Urbach energy (Delta E) were evaluated. The density, molar volumes, molar refraction (R-m), molar polarizability (alpha(m)), metallization criterion (M-c), electronic polarizability of oxide ions (alpha(O-2)), and optical basicity (Lambda) were estimated. Moreover, the nonlinear refractive index (n(2)), third-order nonlinear susceptibility (chi((3))), and nonlinear absorption coefficient (beta) were observed. It was found that the linear and nonlinear refractive indexes increase with decreasing the optical energy gap.