Abstract

Ion implantation is a known method for producing isolated nanoclusters in a given matrix. We have reported large nonlinear susceptibilities for ion implanted silicon in fused silica, 10⁻⁷ esu for 3–4 nm clusters at λ = 355 nm and 10⁻⁶ esu for 5–6 nm clusters at λ = 532 nm respectively.¹ The correlation between wavelength and the cluster size in these samples prompted us to study the wavelength dependence of the nonlinear constants to better understand the number of photons involved in the nonlinear process. Based on new experiments for the 5-6 nm clusters described below, we propose that the nonlinearity originates as a result of two photon absorption process that is enhanced by a very short lived, size dependent transition.

© 1999 Optical Society of America