Gold nanoparticle assemblies: interplay between thermal effects and optical response

Gold nanoparticle assemblies present an optical response which is very sensitive to different phenomena of thermal origin. In a recent paper, we have described how the interaction of light with matrix-embedded gold nanoparticles can result in the generation of thermal excitations. Here we show how thermal processes can affect the optical response of a nanoparticle assembly. We then connect both aspects and finally point out their involvement in the nonlinear optical response of nanocomposite media. This allows us to tackle two key issues in the field of third-order nonlinear properties of gold nanoparticles: The influence of the generalized thermal lens in the long laser pulse regime and the hot electron contribution to the gold particle intrinsic third-order susceptibility, including its spectral dispersion and intensity-dependence.