Polarization router in radiative near-field based on dielectric nano-elliptical cylinders

Abstract

We propose a metasurface-based polarization router constructed by nano-elliptical cylinders. The router combines the functions of lens and blaze grating to sort harvest and sort polarized light in the radiative near-field. Different from most metasurfaces, which usually aim for 2π phase modulation, the TiO2 meta-atom, with complex amplitude modulation, has a thickness of only 300 nm corresponding to π phase modulation. Though simultaneously manipulating the amplitude and phase of the meta-atom, we demonstrated a polarization router with exceptional capabilities in splitting both x- and y-polarization light in the radiative near-field. Blocking factors monitored at the corresponding x- and y-polarization pixels are 16.33 and 29.19, respectively. These remarkable results pave the way for promising applications, such as automotive sensing and polarization imaging.