High-order optical nonlinearities in plasmonic nanocomposites—a review

Abstract

Composites consisting of metal nanoparticles (NPs) embedded in dielectric media may present large nonlinear optical response due to electronic transitions in the NPs. When the metal NPs are suspended in liquids or embedded in solid substrates, the obtained composites may present high-order optical nonlinearities (HON) beyond the third-order nonlinearity, usually studied for most materials. Moreover, it is observed that the magnitude and phase of the effective high-order susceptibilities can be controlled by adjusting the light intensity, I, and the volume filling fraction, f, occupied by the NPs. Therefore, the sensitivity to the values of I and f allowed the development of a nonlinearity management procedure for investigation and control of various phenomena, such as self- and cross-phase modulation, spatial modulation instability, as well as bright and vortex solitons stabilization, in media presenting relevant third-, fifth-, and seventh-order susceptibilities. As a consequence, it is reviewed in this paper how the exploitation of HON in metal–dielectric nanocomposites may reveal new ways for optimization of all-optical switching devices, light-by-light guiding, as well as the control of solitons propagation for long distances. Also, theoretical proposals and experimental works by several authors are reviewed that may open the possibility to identify new high-order phenomena by applying the nonlinearity management procedure. Therefore, the paper is focused on the properties of metal nanocomposites and demonstrates that these plasmonic composites are versatile platforms for high-order nonlinear optical studies.