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

In this paper we present the design, fabrication, and characterization of broadband and wide-angle metasurface-based optical waveplates. Such nanostructured waveplates are formed by an array of rectangular gold nanopatches on a solid gold layer backed glass spacer. Through engineering the anisotropic resonant response and inter-element coupling of the nanopatch array, highly efficient polarization conversion can be achieved to generate an arbitrary state-of-polarization in a broad wavelength and wide angular range. As a proof-of-concept example, a near-infrared quarter-wave metasurface waveplate is experimentally demonstrated, showing a polarization conversion ratio higher than 91% and energy efficiency over 86% within a wavelength range from 630 nm to 1290 nm.