Nonlinear optical properties and optical limiting measurements of graphene oxide – Ag@TiO2 compounds

• The optical limiting threshold of Graphene Oxide was decreased by addition of a small amount of Ag@TiO2 core-shells.
• The nonlinear absorption coefficient of Graphene Oxide was increased by addition of a small amount of Ag@TiO2 core-shells.
• Thermal properties of Graphene Oxide were enhanced by addition of Ag@TiO2 core-shells.
• Good agreement of our results with other published works was achieved.

In this work Graphene Oxide (GO), Ag@TiO2 core-shells and GO-Ag@TiO2 compounds were prepared and experimentally verified. Using a low power laser diode with 532 nm wavelength, the magnitude and the sign of the nonlinear refractive index and nonlinear absorption were determined by the Z-scan technique. It was observed that the nonlinear absorption of GO-Ag@TiO2 mixture was higher than pure GO. The optical limiting effect of these samples was also investigated using the 2nd harmonics of a pulsed Nd-YAG laser at 532 nm. Our results showed that the sole Ag@TiO2 didn't show any appreciable optical limiting effect, however after just mixing with graphene oxide the threshold of optical limiting was increased and the compound showed an enhancement of optical limiting behavior compared to GO itself. The presented results are discussed and compared with other literature reports.