Nonresonant third-order optical nonlinearity of quantum-confined CdS clusters: A third harmonic generation study

Abstract

We report the first study, to the best of our knowledge, of the nonresonant third-order optical nonlinearity of quantum-confined CdS clusters using third harmonic generation from 1.91 to 0.64 μm. We observe that the nonlinearity increases with the increase in the cluster size. The intrinsic, nonresonant χ(3)CdS for ∼30, ∼15 Å thiophenolate-capped CdS clusters and [Cd10S4(SPh)16]−4 molecular clusters are 3.3×10−10, 2.5×10−11, 4.7×10−12 esu, respectively. To utilize this large nonresonant nonlinearity it is necessary to incorporate these clusters into a sample in high concentrations.