The nonlinear optical response for index-matched, non-absorbing immiscible phases (liquid-solid, liquid-liquid, solid-solid) has been determined by means of open aperture z-scan measurements. In mixtures where one constituent shows a relatively high optical nonlinearity, rapid and reversible transformation to a light-scattering state is observed under conditions where a critical incident light fluence is exceeded. This passive broadband response is induced by a transient change in the dispersive part of the refractive index, and is based upon the Christiansen-Shelyubskii filter that at one time was used as a means to monitor the
temperature of glass melts. Modeling studies are used to simulate scattering intensities in such textured composites as a function of composition, microstructure, and constituent optical properties. Results provide a rational approach to the selection of materials for use in these limiters. Challenges to preparing dispersed phase mixtures and their response to 532 nm nanosecond pulsed laser irradiation are described.