Self-Healing of Gold Nanoparticles in the Presence of Zinc Phthalocyanines and Their Very Efficient Nonlinear Absorption Performances

We found that a gold nanoparticles (AuNP) solution shows very good nonlinear absorption properties in the nanosecond time regime at 532 nm, also at high fluences, when zinc phthalocyanines are present. The enhanced nonlinear response is due to the self-healing of gold nanoparticles, which do not undergo the fast photoinduced fragmentation usually observed during irradiation with intense laser pulses. The self-healing mechanism can be of general interest when intense laser pulses interact with plasmonic nanostructures in the presence of organic chromophores.