Polarization-selective dual-wavelength gap-surface plasmon metasurfaces

In this paper, we present a general method to realize polarization-selective dual-wavelength gap-surface plasmon metasurfaces (GSPMs), which are composed of strongly anisotropic meta-atoms periodically arranged in a rectangular lattice with two degrees of freedom to independently control the reflection phase and amplitude of orthogonal linear polarizations at two discrete wavelengths. We design and demonstrate dual-wavelength GSPMs as polarization beam splitters and focusing metamirrors operating at 850 and 1550 nm simultaneously. Our work provides a general approach to design multiwavelength, multifunctional metasurfaces with various potential applications.