We report the observation of interband two-photon absorption (TPA) saturation in cadmium sulfide nanocrystals (CdS NCs) under intense femtosecond laser excitation with 1.6-eV photon energy. The observation has been compared to interband TPA saturation in bulk CdS under the same experimental conditions. By using both Z-scan technique and transient absorption measurement, the saturation intensity has been determined to be 190 GW/cm^2 for CdS NCs of 4-nm diameter, which shows two orders of magnitude greater than that for CdS bulk crystal. The results are in agreement with an inhomogeneously-broadened, saturated TPA model.
@article{arxiv.cond-mat/0510402,
title = {Observation of Interband Two-Photon Absorption Saturation in CdS Nanocrystals},
author = {Jun He and Jun Mi and Heping Li and Wei Ji},
journal= {arXiv preprint arXiv:cond-mat/0510402},
year = {2007}
}