Improving optical limiting of cw lasers with fullerene functionalized gold nanoparticles

In the attempt to improve optical limiting of cw lasers by exploiting the thermo-optic effect exhibited by gold nanostructures, we investigated two coupled systems consisting of either gold nanoparticles (AuNPs) or gold-silica core-shell (AuNSs), both functionalized with a thiolated-fulleropyrrolidine (C60Py). We measured the optical limiting behavior under cw illumination at 514 and 647 nm, resonant with the surface plasmon resonance at around 520 of AuNPs and at 650 nm of AuNSs, respectively. Temporal response analysis shows the variation of transmitted irradiance in a 300 milliseconds time interval, corresponding to the blinking time of the human eye. Comparing the present results we those previously obtained for AuNPs1 we demonstrate an improvement of the response of functionalized nanoparticles (AuNPs- C60Py) with respect to bare AuNPs.