Nonlinear properties of nanoscale antennas

Nanoscale antennas are optical devices that can facilitate the localization and transfer of electromagnetic (EM) energy at the nanometer length scale. In this review, we discuss nanoscale antennas based on coupled metal nanoparticles that exhibit strong optical nonlinear behavior. These distinct properties are a consequence of the large EM field concentration at the localized plasmon resonance frequency, which can enhance the local strength of light-matter interactions. Specifically, we will highlight how optical nanoantennas can boost nonlinear processes, resonant energy transfer between surface plasmons and excitons, and lasing action in the presence of gain materials.