A generalized Drude–Lorentz model for refractive index behavior of tellurite glasses

Abstract

An extension of Drude–Lorentz model based on the fractional approach was used to investigate quantitative measurement of refractive index as a function of wavelength of Tellurite glasses. Tellurite glass samples were synthesized by conventional melt-quenching method with the composition of 65TeO2–15Li2O–20ZnO undoped and doped with different concentrations of Er2O3. Refractive index measurements were performed using the Brewster angle technique with polarized lasers at 442, 532, 594 and 633 nm as light source. From the Sellmeier’s coefficient it was possible to obtain the behavior of refractive index from 0.35 to 1.8 μm. The analytical solution obtained from the generalized Drude–Lorentz model was used to investigate the experimental data of refractive index behavior obtained by the two-pole Sellmeier’s equation showing that the mean polarizability increases with Er2O3 concentration and this behavior can be related to a collective fractal character of the material.