Size and shape effects on the nonlinear optical behavior of silver nanoparticles for power limiters.

The optical limiting behavior of silver nanoparticles with different sizes and shapes is investigated and compared to the optical limiting performance of conventional carbon black suspension (CBS). The optical limiting behavior is characterized by means of nonlinear transmittance and scattered intensity measurements when submitted to nanosecond pulsed Nd:YAG lasers operating at the fundamental or the second harmonic wavelength. We found that the optical limiting effect is strongly particle size dependent and the best performance is achieved with the smaller particles. Moreover, it is shown that the surface plasmon resonance is not the main effect responsible for the nonlinear processes. A theoretical model based on the computation of the Mie scattering functions is exposed, and it is shown that the experimental results can be well explained from the calculations.