Self focusing-self defocusing transformation in an organometalic fullerene-C-60 derivative

We studied the nonlinear refraction properties of an organmetallic fulleren e-C-60 derivative fac and mer-[bis(1,2-diphenylphosphino) ethane] (tricarbo nyl)(eta(2)-fullerene-C-60) chromium by using Z-scan method. We also invest igated the nonlinear refraction behavior of exited-state nonlinear optical materials and the switching between self-defocusing and self-focusing cause d by the refrangibility of high excited state based on rate-equation theory . The transformation intensity was worked out,and the experiment was simula ted numerically. The theoretical results agrees well with the experimental data.