ABSTRACT In this paper we review our recent advances in subwavelength plasmonic structures in linear and nonlinear regimes. We show several examples of subwavelength plasmonic devices in different configurations and schemes. We emphasize how these devices can be exploited for many applications, such as sensing, spectroscopy, photovoltaics and optical communications. Finally we will illustrate some challenges that are still open and need to be fulfilled. Keywords: plasmonics, plasmonic resonance, scattering, field enhancement, thin film, nonlinear harmonic generation. INTRODUCTION The propagation of Surface Plasmon Polaritons (SPPs) has gained great interest in the last decades since it has been demonstrated that their excitation on metal gratings or metal nanostructures can be usefully exploited to solve several problems relative to many applications, such as Raman spectroscopy, sensing, data storage, light emission and amplification as well as absorption enhancement for energy harvesting purpose
