Third order optical nonlinear studies and its use to estimate thickness of sandwiched films of tetra-phenyl porphyrin derivatives

Abstract

Third-order nonlinear optical properties of tetra-phenyl porphyrin (H[Formula: see text]TPP) derivatives viz., H[Formula: see text]TPP(OH)[Formula: see text] and Zn(II)TPP doped in boric acid glass thin films were measured using single beam Z-scan and forward degenerate four-wave mixing (DFWM) techniques. Excited state lifetimes and absorption cross-sections were estimated from these experiments. Thickness of the porphyrin doped sandwich glass films were determined using DFWM technique for the first time. The values of nonlinear refractive index ([Formula: see text]) obtained for these systems are are found to be sensitive to the nature of substituents in porphyrin molecule. These results are interpreted in terms of delocalized [Formula: see text] electrons contributing to the third-order optical nonlinearity.