Investigation of picosecond optical nonlinearity in porphyrin metal complexes derivatives

Porphyrin metal complex derivatives were experimentally studied using the Z-scan technique and the optical Kerr gate method with picosecond pulses at 532 nm. The sign and magnitude of the nonlinear refraction and nonlinear absorption were determined for a negatively charged meso-tetrakis(p-sulfonatophenyl)porphyrin (TPPS4) and a positively charged meso-tetrakis(4-N-methyl-pyridiniumyl)porphyrin (TMPyP) in their free-base forms and their Fe(III) and Mn(III) complexes. The results were phenomenologically understood and the origin of the nonlinearity was inferred.