One of the goals of optics is to realise ultra-fast devices capable of transmitting and manipulating information with switching times limited only by an optical cycle of light (thousands of attoseconds). This is possible by exploiting ‘non-linear’ optical processes, in which an optical signal is altered by the presence of a second light stimulus; these processes require mediation by specific materials.
A group of researchers from the Department of Physics of Politecnico di Milano used a metasurface, i.e., a two-dimensional matrix less than a micron thick – a hundred times thinner than a hair – composed of ‘meta-atoms’, elements smaller than the wavelength of light. The research, coordinated by Professors Michele Celebrano and Marco Finazzi and published in Nature Nanotechnology, demonstrates how a metasurface, by exploiting interference between nonlinear optical processes, is able to perform true optical switching of emitted light, converting incident infrared light into visible light and offering the possibility, in principle, of processing information at the rate of one trillion bits per second.
Over the past decade, metasurface research has been revolutionising the field of optics and is a cornerstone of the new EssilorLuxottica Smart Eyewear Lab, the research centre in collaboration with Politecnico di Milano for the design of the smart glasses of the future.
