Nonlinear absorption reversing between an electroactive ligand and its metal complexes.

We present the nonlinear absorption investigation of an electroactive ligand and two ruthenium and iron metal complexes under 532 nm, 30 ps laser excitation, by the "open aperture" Z-scan technique. Significant nonlinear optical parameters have in all cases been measured, while the nonlinear attribute has been found to change from saturable to reverse saturable absorption between the initial ligand and its complexes.