Fig. 6

a Illustration of input and output electric fields in a 4-by-4 simulation. b Poincaré sphere representation of light polarization state evolution in b single layer half-wave plate. Red and yellow curves correspond to half-wave plates with different fast axis orientations and c two-layer half-wave plate (green) and three-layer half-wave plate (blue). Relations of S3 parameter of three structures with respect to d wavelength and e incident angle