Nonlinear absorption in tetrathia[22]porphyrin(2.1.2.1)s: visualizing strong reverse saturable absorption at non-resonant excitation

Abstract

The nonlinear optical absorption properties of three meso-substituted aromatic, neutral tetrathia[22]porphyrin(2.1.2.1) compounds were investigated using an open aperture Z-scan technique at 527 nm with a pulse width of 100 ns in dichloromethane. The responses obtained were accounted for by invoking reverse saturable absorption arising due to strong excited state absorption. Both ground and excited state absorption cross-sections are reported, which follow the same trend as the respective structural parameters.