Size effect of optical limiting in gold nanoparticles

Optical limiting performances in gold nanoparticles with different radii of 15 nm, 25 nm, 50 nm and 70 nm are investigated by using 532 nm nanosecond laser pulses. The investigation shows that the optical limiting capability is size-dependent, but does not increase monotonously with size of particle. The optimal size of gold nanoparticle for optical limiting is found to be 25 nm. The results are analyzed in terms of absorption-induced nonlinear scattering and surface layer.