Optical devices as thin as atoms

Abstract

The functional properties of traditional optical structures such as lenses are linked to their inherent three-dimensional (3D) shape, which is often fixed upon fabrication. Their 3D nature also prevents integration of these optical elements into tightly packed systems. Metasurfaces—2D metamaterials that can control the propagation and scattering of light—are promising for compact, flat optics. These materials leverage strong interactions of light with metal and semiconductor nanostructures to control the flow of light with geometric features. However, dynamically tuning the optical properties of metasurfaces remains difficult because they tend to be only weakly dependent on external stimuli such as an electrical field. Reducing the dimension of a metasurface to the atomic scale could enable dynamic tuning and strong lightmatter interaction through the quantum size effect, which allows materials to more effectively absorb and emit light at a specific wavelength.