Nonlinear optical properties of Ge-SiO2 thin films

Nonlinear optical properties of Ge nanocrystallites embedded in SiO₂ (Ge-SiO₂) thin films prepared by the ion-beam sputtering technique have been studied by the Z-scan technique. The large values of nonlinear absorption coefficient and nonlinear refractive index of the samples were estimated respectively. Thus, the third-order optical nonlinear susceptibility χ³ obtained for Ge-SiO₂ thin film specimens is several orders of magnitude larger than that of the bulk Ge crystals. The results indicate that Ge-SiO₂ thin films showing enhanced optical nonlinearity have bright prospects as suitable nonlinear optical materials for optical function devices