Optical limiting behaviour of Zinc-Phthalocyanines in polymeric matrix

Phthalocyanines are promising molecules which present very attractive properties for nonlinear optical applications of both second and third orders. Different solutions of zinc phthalocyanine in toluene at increasing concentration were investigated by spectroscopic analysis in order to get the best conditions for the realization of films in poly(methyl methacrylate). Some films of zinc phthalocyanine in polymeric matrix were realized and their nonlinear optical behavior was characterized. The ratio by weight of the compound to the host polymer was varied between 0.004% and 0.15%. In this range all samples show a low degree of aggregation. The nonlinear optical behavior of the films was evaluated by measuring nonlinear transmission. The measurements of nonlinear transmission were carried out at 532 nm using a nanosecond Nd:YAG laser followed by an optical parametric oscillator, and a nonlinear response was observed for the two highest concentrations (0.083% and 0.15%).