Dispersion of the refractive index of a samarium-doped Se$_{95}$Te$_5$ chalcogenide glassy semiconductor

The transmission spectrum of a Se$_{95}$Te$_5$ chalcogenide glassy semiconductor doped with samarium (0.05, 0.1, 0.25, 0.5, and 1 at%) is studied; the Swanepoel method and the single-oscillator model are used to determine the oscillator energy $E_0$, dispersion energy $E_d$, optical width of the band gap $E_g$, and linear $(n)$ and nonlinear $(n_2)$ refractive indices. The changes in the values of these parameters as a result of doping are attributed to modification of the local structure and to a change in the concentration of defect states.