Polarization multiplexing metasurface for dual-band achromatic focusing

We propose a dual-band achromatic focusing metasurface based on polarization multiplexing and dispersion engineering. An anisotropic resonant phase meta-atom is designed to realize independent nonlinear phase manipulation along the orthogonal directions. Achromatic focusing metasurtace and broadband reflectarray antenna are further constructed in the microwave region with a computer-assisted particle swarm optimization algorithm. The standard deviation of focus offset at 11-16 GHz (for x-polarization) and 18-24 GHz (tor y-polarization) are compressed to 19.83% and 16.60% of the dispersive metasurface, respectively. The radiation gains of the reflectarray antenna increase by an average of 19.49 dB and 15.08 dB in the broadband region compared with the bare standard rectangle waveguides. Furthermore, such an achromatic metasurface can be utilized to realize different functions with polarization selectivity and applied to other frequency ranges, which holds great promise in integrated optics. (C) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

Automated summary

We propose a dual-band achromatic focusing metasurface based on polarization multiplexing and dispersion engineering. The metasurface utilizes anisotropic resonant phase meta-atoms for independent nonlinear phase manipulation along orthogonal directions. The study demonstrates the construction of the metasurface and broadband reflectarray antenna using a computer-assisted particle swarm optimization algorithm. Experimental results show that the metasurface achieves achromatic focusing and significant broadband reflection gains.