Picosecond Kinetics and Reverse Saturable Absorption of Meso-Substituted Tetrabenzoporphyrins

Abstract

The mechanism of reverse saturable absorption of meso-substituted tetrabenzoporphyrins was studied by means of picosecond transient spectroscopy. Characteristic 1(π,π*), 3(π,π*), and (d,d) transitions have been observed. The kinetics of the excited states vary with metal substitution. The nonlinear transmission of benzoporphyrins was measured, and the excited-state absorption was determined to be the dominant optical limiting mechanism. The results agreed very well with a five-level model.