Ultrathin Metasurface Laser Beam Shaper

Driven by ground-breaking applications in various scientific communities, metamaterial research has experienced rapid growth over the past decade. Metasurfaces, the new emerging field of metamaterials, have aroused considerable interest due to their capability of arbitrary manipulation of the phase profile at the interface. Here, an ultrathin (40 nm) broadband laser beam shaper for visible and near-infrared light is realized experimentally by using metasurfaces consisting of a monolayer of metallic nanorods with spatially varying orientations. The abrupt phase change occurs when a circularly polarized light wave is converted to the opposite handedness. The phase distribution of the planar devices is obtained by using the Yang-Gu algorithm and then encoded to the spatial orientations of the nanorods. This approach can be used for information processing and other phase-related techniques.