Generation of Concentric Space-Variant Linear Polarized Light by Dielectric Metalens

Miniaturized flat and ultrathin optical components with spatial and polarization degrees of freedom are important for optical communications. Here, we use nanostructures that act as tiny phase plates on a dielectric metalens to generate a concentric polarization beam with different orientations along the radial direction. The important discoveries are that (1) the circularly polarized light can be converted into linearly polarized states with a different orientation at near field and that (2) this orientation is strongly correlated to the rotation of the nanostructures on the metalens. Stokes parameters are utilized to investigate the comprehensive polarization states embedded in the optical intensity along the propagation direction. The variation of the spatial polarization states transformed by the dielectric metalens can be properly mapped onto the Poincare sphere. We believe that the variety of spatial polarizations within a miniaturized configuration provides a new degree of freedom for diverse applications in the future.

Automated summary

By utilizing nanostructures on a dielectric metalens, concentric polarization beams can be generated with the conversion of circularly polarized light to linearly polarized states, which are strongly correlated to the rotation of the nanostructures, highlighting important discoveries.