Enhanced excited-state optical nonlinearities in a novel metallophthalocyanine compound (C₁₂H₂₅O)₈PcPb

Nonlinear absorption in a novel metallophthalocynine compound (C₁₂H₂₅O)₈PcPb was investigated by the Z-scan technique with the irradiation of 8 ns laser pulses at the wavelength of 532 nm. The large optical limiting response was observed. The nonlinear absorption cross section was obtained by the simulation with a simplified rate equation model in which excited triplet-triplet state absorption is dominant. The excited-state absorption cross section and its effective ratio to the ground-state absorption cross section are larger than those of C₆₀. The attenuation factor for (C₁₂H₂₅O)₈PcPb is 2.5 times larger than that of C₆₀, which is induced by the heavy atom lead interposition.