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.

AbstractLike amplitude, phase and frequency, polarization is one of the fundamental properties of light, which can be used to record, process and store information. Optical metasurfaces are ultrathin inhomogeneous media with planar nanostructures that can manipulate the optical properties of light at the subwavelength scale, which have become a current subject of intense research due to the desirable control of light propagation. The unprecedented capability of optical metasurfaces in the manipulation of the light’s polarization at subwavelength resolution has provided an unusual approach for polarization detection and arbitrary manipulation of polarization profiles. A compact metasurface platform has been demonstrated to detect polarization information of a light beam and to arbitrarily engineer a polarization profile that is very difficult or impossible to realize with conventional optical elements. This review will focus on the recent progress on ultrathin metasurface devices for polarization detection and realization of customized polarization profiles. Optical metasurfaces have provided new opportunities for polarization detection and manipulation, which can facilitate real-world deployment of polarization-related devices and systems in various research fields, including sensing, imaging, encryption, optical communications, quantum science, and fundamental physics.

Three-dimensional (3D) light fields with spatially inhomogeneous polarization and intensity distributions play an increasingly important role in photonics due to their peculiar optical features and extra degrees of freedom for carrying information. However, it is very challenging to simultaneously control the intensity profile and polarization profile in an arbitrary manner. Here we experimentally demonstrate a metalens that can focus light into an arbitrarily shaped focal curve with a predefined polarization distribution. The efficacy of this approach is exemplified through the demonstration of focused curves in 3D space ranging from simple shapes such as a circle to topologically nontrivial objects such as a 3D knot with controlled local polarization states. This powerful control of the light field would be technically challenging with their conventional counterparts. Our demonstration may find applications in beam engineering and integration optics.

No abstract

No abstract

No abstract

No abstract

No abstract