Metasurfaces for phase/polarization manipulation and imaging

Metasurfaces, the two-dimensional counterpart of metamaterials, enable an unprecedented capability in manipulating the phase, polarization and amplitude of electromagnetic waves. Here, we have proposed and experimentally demonstrated an approach to realize terahertz multi-foci metalens with polarization-rotated focal points. The THz polarization-dependent imaging is demonstrated based on the multi-foci metalens. In addition, the THz metalens with asymmetric focusing that can unidirectionally focus the incident THz waves into focal point was also designed and experimentally demonstrated.