Nonlinear optical absorption of InAs nanocrystals embedded in SiO₂ thin films

Nonlinear optical absorption of InAs nanocrystals embedded in SiO₂, films prepared by radio-frequency magnetron cosputtering was studied by Z-scan technique using a single Gaussian beam of a He-Ne laser (633 nm). Both two-photon absorption and saturation absorption were observed. The enhanced third-order nonlinear optical absorption coefficients were obtained in the composite film. Our results indicate that the type and magnitude of the nonlinear optical absorption coefficient of the composite films are related to the average size of the nanocrystals.