title: “Plasmonics” in free space: observation of giant wavevectors, vortices, and energy backflow in superoscillatory optical fields
abstract: Evanescent light can be localized at the nanoscale by resonant absorption in a plasmonic nanoparticle or taper or by transmission through a nanohole. However, a conventional lens cannot focus free-space light beyond half of the wavelength <i>λ</i>. Nevertheless, precisely tailored interference of multiple waves can form a hotspot in free space of an arbitrarily small size, which is known as superoscillation. Here, we report a new type of integrated metasurface interferometry that allows for the 
journal: Light Science & Applications