Resonant third-order optical nonlinearities of highly-substituted phthalocyanine derivatives

Third-order optical nonlinearities of three highly-substituted phthalocyanines (Pcs) containing central metal atom VO, Al, and Cu were investigated under resonant conditions by femtosecond degenerate four-wave mixing. The dynamics of the nonlinear response was found to be strongly dependent on the nature of the central metal atom and molecular stacking form. The electronic molecular hyperpolarizability of the Pcs was evaluated and compared with their structure-related analogues. The electronic third-order susceptibilities of the solid films containing the Pcs were determined to be in the range of 10(-10) to 10(-9) esu. We attempt to give structure-property relationships in these macrocyclic compounds.