Fig. 1. A unit with high-efficiency polarization conversion capability. (a) Design diagram of unit structure; (b) when frequency range is from 60 to 100 GHz, co-polarization ratio and corresponding reflection phase of a metasurface constructed using unit structure in (a) for inearly polarized light sources; (c) polarization conversion efficiency between circularly polarized lights

Fig. 2. Metasurface coupler that couples free-space electromagnetic waves into surface wave modes as SSPP modes. (a) Dispersion relationship between two end flat waveguides of coupler; (b) correspondence between rotation angle θ of unit structure and phase gradient

Fig. 3. On left side of coupler is focusing beam excited by right circularly polarization (RCP) light decomposed by linearly polarization light, and on right side is Bessel beam excited by left circularly polarization (LCP) light decomposed by linearly polarization light

Fig. 4. Influence of changing opening angle α value of unit structure on its performance. (a) Correspondence between resonant phase of structure and αwhen frequency is 75 GHz; (b) influence of opening angle α on structure’s reflectance and reflection phase when frequency is 75 GHz

Fig. 5. Wavefront-independent control effect. (a) Full width at half wavelength of central field intensity of focusing beam at x=-15.45, -13.65, and -11.85 mm; (b) full width at half wavelength of central field intensity of Bessel beam at x=12.45, 19.65, and 26.85 mm; (c) electric field patterns of focusing beam and Bessel beam