Linear and nonlinear refractive index of As–Se–Ge and Bi doped As–Se–Ge thin films

The present work reports the linear and nonlinear refractive index for $(As2Se3)90Ge10$ and $[(As2Se3)90Ge10]95Bi5$ thin films. The formulation proposed by Fournier and Snitzer has been used to predict the nonlinear behavior of refractive index. The linear refractive index and Wemple–DiDomenico parameters were used for the determination of nonlinear refractive index in the wavelength region 0.4 to $1.5μm$⁠. Linear refractive index has been determined using the well known Swanepoel method. This is observed that nonlinear refractive index increases linearly with increasing linear refractive index. With Bi addition this has been found that nonlinear refractive index increases by 2.4 times, while on comparing with pure and doped silica glasses results are 2–3 orders higher. Density and molar volume has also been calculated. The obtained results may lead to yield more sensitive optical limiting devices and these glasses may be used as an optical material for high speed communication fibers.