Ge28Se60Sb12/PVA COMPOSITE FILMS FOR PHOTONIC APPLICATIONS

New chalcogenide based composite films were prepared and characterized. The optical characterization has been done by analysing the transmittance (T) and reflectance (R) spectra in the spectral region 200-2000 nm. It was found that the optical energy gap increases (2.51eV to 3.56 eV) with decreasing Ge28Se60Sb12 content. The results are interpreted in terms of cluster size of the colloid solution which depends on concentration of Ge28Se60Sb12. Dispersion of refractive index has been analysed using the Wemple-DiDomenico single oscillator model. The refractive index (n), extinction coefficient (k), dispersion parameters, (Eo, Ed), static refractive index(no), static dielectric constant have been calculated for the investigated films. Generalized Miller's rule and linear refractive index are used to find the nonlinear susceptibility and non linear refractive index of thin films.