Nonlinear optical properties of ion implanted silicon nanostructures in silica

Large nonlinear susceptibilities for ion implanted silicon in fused silica are discussed. The samples were prepared by implanting Si into fused silica matrices followed by annealing at 1100 °C in flowing Ar and 4% H₂. After annealing, the cluster size was found to be 5-6 nm. The refractive index of the composite material was calculated to be 2.2 while the absorption coefficient of these samples exhibit two resonances: a strong absorption peak centered near 400 nm and another weaker absorption centered at 580 nm.