Recent measurements of transmission versus fluence for a methanol-solvated asymmetric pentaazadentate porphyrin-like (APPC) cadmium complex, [(C6H4-APPC)Cd]Cl, showed the limitations of current energy-level models in predicting the transmission behavior of organic reverse saturable absorbers at fluences greater than 1 J/cm². A new model has been developed that incorporates higher-order triplet processes and accurately fits both nanosecond and picosecond transmission-versus-fluence data. This model has provided the first known determination of a higher triplet excited-state absorption cross section and lifetime for an APPC complex and also described a previously unreported feature in the transmission-versus-fluence data. The intersystem crossing rate and the previously neglected higher triplet excited-state absorption cross section are shown to govern the excited-state population dynamics of methanol-solvated [(C6H4-APPC)Cd]Cl most strongly at more-practical device energies.
© 2005 Optical Society of America
(160.4330) Materials : Nonlinear optical materials
(160.4890) Materials : Organic materials
(160.6990) Materials : Transition-metal-doped materials
(190.0190) Nonlinear optics : Nonlinear optics
(190.4400) Nonlinear optics : Nonlinear optics, materials
Michael M. McKerns, Wenfang Sun, Chris M. Lawson, and Gary M. Gray, "Higher-order triplet interaction in energy-level modeling of excited-state absorption for an expanded porphyrin cadmium complex," J. Opt. Soc. Am. B 22, 852-861 (2005)