The Nonlinear Optical Response of Substituted Phthalocyanines and Porphyrins

The cubic polarizabilities, 〈γ〉, of over thirty substituted phthalocyanines have been previously measured at 1064 nm and/or at 597 nm. 〈γ〉 depends dramatically on the molecular structure and central metal atom.1,2 In this paper we report the concentration dependence of the temporal response of χ(3)xxxx and χ(3)xyyx of metal free tetrakis(cumylphenoxy)phthalocyanine (H2Pc(CP)4). Further, the nonlinear optical (NLO) response of several porphyrins, including one substituted with a long chain, carotenoid polyene are reported. For each of these materials the time and polarization dependences observed in degenerate four-wave mixing (DFWM) experiments show that optical pumping contributions enhance the NLO response.