Optical Second Harmonic Generation in Plasmonic Nanostructures: From Fundamental Principles to Advanced Applications

TLDR

Plasmonics is a key area of nanoscience, and nonlinear plasmonics has recently focused on nonlinear optical processes in plasmonic nanostructures. This review aims to comprehensively examine the physical mechanisms of second harmonic generation in plasmonic nanostructures, contrasting them with linear responses and outlining future directions. Key applications include using SHG for nonlinear optical characterization of nanostructure shapes and for optimizing laser beams at the nanoscale.

Abstract

Plasmonics has emerged as an important research field in nanoscience and nanotechnology. Recently, significant attention has been devoted to the observation and the understanding of nonlinear optical processes in plasmonic nanostructures, giving rise to the new research field called nonlinear plasmonics. This review provides a comprehensive insight into the physical mechanisms of one of these nonlinear optical processes, namely, second harmonic generation (SHG), with an emphasis on the main differences with the linear response of plasmonic nanostructures. The main applications, ranging from the nonlinear optical characterization of nanostructure shapes to the optimization of laser beams at the nanoscale, are summarized and discussed. Future directions and developments, made possible by the unique combination of SHG surface sensitivity and field enhancements associated with surface plasmon resonances, are also addressed.