Noncritical microemulsion as nonlinear optical material

Abstract

Water in oil microemulsions are systems of spherical droplets of water coated by a monolayer of surfactant molecules, immersed in oil. Initially we have studied the optical nonlinear behavior of water in oil microemulsion by the Self-Phase-Modulation of a gaussian laser beam by an optically thin film. The material is WAD (water/AOT/decane, where AOT denotes sodium-bis-di-ethyl-sulfosuccinate) far from critical points and near the percolative transition from electrically insulating to electrically conducting. We have observed optical nonlinearity in the L2 area of the phase diagram, near the percolation line and far from the one-phase two-phase boundary line. In this point, the material turbidity is very low. Strong optical nonlinearity has been reported. Nonlinear optical effects in a Water/AOT/Decane (WAD) microemulsion have been experimentally studied also in a pump probe configuration. We detect the variation of the on axis optical intensity of the probe beam as generated by the concentration profile induced in an optically thin film of microemulsion by the pump beam. Results seem to suggest the hypothesis of a chain like shape of the clusters.