Demonstration of broadband and wide-angle optical metasurface-based waveplates

We present the design, fabrication, and characterization of broadband and wide-angle metasurface-based plasmonic waveplates. Such nanostructured waveplates are formed by an array of rectangular gold nanopatches on a dielectric spacer backed by a solid gold layer. By engineering the anisotropic resonant response of the nanopatch array and tailoring the light interference in the dielectric spacer, highly efficient polarization transformation can be achieved over a broad wavelength range with a wide field-of-view. As a proof-of-concept example, a half-wave plate at the near-infrared regime is demonstrated, showing a polarization conversion ratio and efficiency both higher than 92% within a wavelength range spanning 640 nm to 1290 nm.