In this work, we demonstrate that the nonlinear response of certain soft-matter systems can be tailored at will by appropriately engineering their optical polarizability. In particular, we deliberately synthesize stable colloidal suspensions with neg
ative polarizabilities, and observe for the first time robust propagation and enhanced transmission of self-trapped light over long distances that would have been otherwise impossible in conventional suspensions with positive polarizabilities. What greatly facilitates this behavior is an induced saturable nonlinear optical response introduced by the thermodynamic properties of these colloidal systems. This in turn leads to a substantial reduction in scattering via self-activated transparency effects. Our results may open up new opportunities in developing soft-matter systems with tunable optical nonlinearities.
