Study of Se based quaternary SePb(Bi,Te) chalcogenide thin films for their linear and nonlinear optical properties

Present paper reports the linear and nonlinear optical properties of Se based quaternary SePb(Bi,Te) chalcogenide thin films. The linear optical properties are evaluated with the help of transmission spectra, recorded in the spectral range of 400–2500 nm, using an UV–vis–NIR spectrophotometer. The linear refractive index (n) is determined using Swanepoel's method and Tauc extrapolation method is used to determine the optical band gap (Eg). The dispersion of refractive index is analyzed using Wemple–DiDomenico (WDD) single oscillator model and static refractive index (n0) has also been reported. The dielectric constants (ɛ0 and ɛi) and optical conductivity (σ) are determined using linear refractive index (n), extinction coefficient (k) and absorption coefficient (α). Volume energy loss (Vel) and surface energy loss (Sel) are also reported for the investigated materials. The nonlinearity of the system under investigation is studied by empirical and semi empirical relation proposed by various researchers. The formulation proposed by Fournier and Snitzer and Tichy and Ticha is used to determine the nonlinear behavior of refractive index. The third order susceptibility χ(3) is also reported in this paper. All the optical parameters are compared for their behavioral change with the incorporation of Pb additive.