Nonlinear light transmission through oxide-protected Au and Ag nanoparticles: an investigation in the nanosecond domain

Stable Au and Ag nanoparticles protected with TiO2, ZrO2, and SiO2 shells show saturable absorption when excited with moderately energetic nanosecond pulses at 532 nm, but exhibit strong optical limiting at higher intensities. The 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.