We formed composite materials with geometries approximating that of th
e Bruggeman model by filling the pores of a porous glass with opticall
y nonlinear fluids spanning a range of linear refractive indices. The
effective linear refractive indices of the composites were measured wi
th a Mach-Zehnder interferometer. The effective nonlinear refractive i
ndices were determined by the Z-scan method. In both cases good betwee
n the experimental data and theoretical predictions was found. (C) 199
7 Optical Society of America.