Third-Order Nonlinear Optical Response of Metal Nanoparticles

Abstract

We present a review of the main results reported in the literature regarding the third-order nonlinear optical response of nanocomposite media consisting of noble metal nanoparticles surrounded by a dielectric host. This phenomenon, known as optical Kerr effect, can be characterized by the intensity-dependent complex optical index of the material or, equivalently, its complex third-order susceptibility. The theoretical basis of the linear and nonlinear optical properties of metal nanoparticles and nanocomposite media are described first. The different third-order optical phenomena which have been observed in such materials are then examined. The dependence of the nonlinear properties on morphological parameters – nature of the dielectric host, metal concentration, particle size and shape – as well as on laser excitation characteristics – wavelength, intensity, pulsewidth – will be explained and illustrated by selected experimental results. The final part points out the important role played by thermal effects in the nonlinear optical response.