Self-complementary zig-zag metasurfaces for designing circular polarizing beam splitters

It is demonstrated that self-complementary zig-zag screens can be used for designing circular polarizing beam splitters. The phase difference between transmission (or reflection) coefficients of orthogonal polarization states is always 90° regardless the operation frequency. Although there is only an exact frequency at which the aspect ratio is 0dB, it is shown that the relative bandwidth for deviations within ±3dB can be as big as 68%. Besides, the periodicity is deeply subwavelength what reduces the diffraction.