Evaluation of nonlinear optical parameters of Se40As60−xSx(x = 10, 20) chalcogenide thin films for photonic applications.

Optical transmissions in the wavelength range 600–2700 nm have been done for the Se₄₀As_60−xS_x (x = 10, 20) chalcogenide thin films. By using these transmission curves, various optical parameters like linear refractive index (n), static refractive index (n₀), nonlinear refractive index (n₂), oscillator energy (E_d), dispersive energy (E₀), band gap energy (E_g), third-order nonlinear optical susceptibility (χ⁽³⁾) and γ have been studied. Wemple-Di-Domenico (WDD) relation has been used for dispersion analysis. To know the possibility of nonlinear switching in Se₄₀As_60−xS_x (x = 10, 20) chalcogenides, nonlinear susceptibility and nonlinear refractive indices are determined by using linear index of refraction and parameters of WDD. On the basis of observed nonlinear optical parameters, the suitability for photonic applications is also discussed. Our experimental results have very good agreement at 10 at.% of S with telecommunication wavelength (~ 1550 nm) at which the maximum optical nonlinearity is found. Due to higher values of nonlinear refractive index, Se₄₀As₅₀S₁₀ is processed better for photonic devices in comparison of Se₄₀As₄₀S₂₀. [ABSTRACT FROM AUTHOR]