An optical bleaching effect in a BiI<sub>3</sub> microcluster colloidal system in the visible region was observed. We find that this effect can be adequately explained by a two-level model with inhomogeneous broadening. By measuring the intensity dependence of the saturated absorption coefficient, we evaluated the third- and fifth-order effective nonlinear-optical susceptibilities of the BiI<sub>3</sub> microcluster colloidal system to be approximately 10<sup>−10</sup> and 10<sup>−15</sup> esu, respectively. By applying the effective-medium approximation, we find that the third-order nonlinear-optical susceptibility of BiI<sub>3</sub> microclusters is approximately 5 × 10<sup>−6</sup> esu.
© 1992 Optical Society of America
Do-Kyeong Ko, Jai-Hyung Lee, Joon-Sung Chang, and Bum Ku Rhee, "Optical bleaching effect in a BiI3 microcluster colloid by saturated absorption spectroscopy," J. Opt. Soc. Am. B 9, 203-207 (1992)