Stable Au and Ag nanoparticles protected with TiO2 ZrO2 and SiO2 shells show saturable absorption when excited t exhibit strong optical limiting at higher intensities. The with moderately energetic nanosecond pulses at 532 nm, but behavior is explained in terms of the induced optical nonlinearity and nonlinear light scattering. The inherent stability of the core-shell structure renders a high laser damage threshold to these materials, making them promising candidates for high energy optical limiting. (C) 2003 Elsevier B.V. All rights reserved.