Localized Waves from Microwaves to Optics: Properties, Applications, and Realizations

The localized transmission of electromagnetic energy is of paramount importance for modern focusing applications, such as wireless power transfer, medical imaging, chipto- chip communications, just to name but a few. While devices capable of generating localized waves at optical frequencies are now widespread, the microwave generation of localized waves is more recent. In this conference paper, we aim at giving the reader a clear perspective on the potentialities offered by localized waves as well as the difficulties that still hinder their full development in certain frequency ranges. Starting from wellconsolidated techniques for the generation of monochromatic localized waves in both the optical and the microwave domain, we discuss the recent progress in the generation of polychromatic localized waves in the microwave range. An outlook on possible future advances in this field will finally be provided.