A Multi-Foci Metalens with Polarization-Rotated Focal Points

Benefiting from the unprecedented capability of metasurfaces in the manipulation of light propagation, metalenses can provide novel functions that are very challenging or impossible to achieve with conventional lenses. Here, an approach to realizing multi-foci metalenses is proposed and experimentally demonstrated with polarization-rotated focal points based on geometric metasurfaces. Multi-foci metalenses with various polarization rotation directions are developed using silicon pillars with spatially variant orientations. The focusing characteristic and longitudinal polarization-dependent imaging capability are demonstrated upon the illumination of a linearly polarized light beam. The uniqueness of this multi-foci metalens with polarization-rotated focal points may open a new avenue for imaging, sensing, and information processing.