Optical nanoantenna arrays loaded with nonlinear materials

Optical nanoantennas loaded by nanoparticles are used to provide large and controllable field enhancement at the nanoscale. Here we show how the introduction of nonlinearities at the nanoload may realize a whole set of all-optical nanoscale functionalities, such as memories, switches and transistors, as a function of whether the nanoantenna is excited ``below'' or ``above'' its resonance frequency. After discussing the main features of this nonlinear nanoantenna operation, we employ its bistable and self-tunable response in a planar array design, which may constitute different nonlinear devices and functionalities of significant interest for optical computing applications.