Frontiers of light manipulation in natural, metallic, and dielectric nanostructures

The ability to control light at the nanoscale is at the basis of contemporary photonics and plasmonics. In particular, properly engineered periodic nanostructures not only allow the inhibition of propagation of light at specific spectral ranges or its confinement in nanocavities or waveguides, but make also possible field enhancement effects in vibrational, Raman, infrared and fluorescence spectroscopies, paving the way to the development of novel high-performance optical sensors. All these devices find an impressive analogy in nearly-periodic photonic nanostructures present in several plants, animals and algae, which can represent a source of inspiration in the development and optimization of new artificial nano-optical systems. Here we present the main properties and applications of cutting-edge nanostructures starting from several examples of natural photonic architectures, up to the most recent technologies based on metallic and dielectric metasurfaces.