Liquid suspensions of submicron particles have been used as a new type of artificial nonlinear optical Kerr medium. Experiments were performed on cw degenerate four-wave mixing and cw self-focusing and self-trapping using such media. The nonlinearities of these media arise from the physical motion of the particles due to radiation pressure forces.1–3 These light forces either pull particles into or out of regions of high light intensity depending on whether their index of refraction is greater or less than that of the surrounding liquid. This results in particle density changes which increase the local index of refraction in regions of high light intensity. The effective nonlinear coefficient n2 describing this intensity dependent refractive index is large (~105 that of CS2) with a response time of milliseconds to seconds governed by the viscosity of the liquid.
© 1982 Optical Society of AmericaPDF Article