Intensity-Dependent Thermally Induced Nonlinear Optical Response of Graphene Oxide Derivative in Hydraulic Oil

The spatial self-phase modulation (sspm) method was used to study the nonlinear optical responses of hydraulic oil containing dispersed nanosheets of reduced graphene oxide (rgo), hydroxylated rgo (rgo-oh), and carboxylated rgo (rgo-cooh). the intensitydependent number of observed symmetric diffraction rings was analyzed to estimate the samples' thermally induced nonlinear refractive indexes and lead to estimated thermo-optical coefficients. based on the observed symmetric diffraction rings, the nonlinear refraction coefficient and thermo-optical coefficient of samples were estimated to be in the order of magnitude of 10-6 cm2/w and 10-2 k-1, respectively. the results indicated that the presence of rgo derivatives significantly enhanced the optical nonlinearity of hydraulic oil.