Fig. 2
Generation of multi-channel perfect HyOPBs. a Planar chiral meta-atom for phase modulation of co-polarized and cross-polarized channels (φco, φRL and φLR) under RCP and LCP incidences. The single-layer chiral metasurface functions as the combination of quarter-wave plate (QWP), spiral phase plate (SPP), Axcion and Fourier lens. b The optical microscope image of the fabricated chiral metasurface. Scale bar: 20 μm. c The measured intensity profiles of perfect HyOPBs and HDPBs with topological charges l0, m0 and n0 of -3, 4 and 1 at 470 nm under RCP, LCP, H- and V-polarized incidences. The white arrow in the left corner of each image corresponds to the input polarization state while that in the right corner depicts the polarization state of analyzers. The first row represents the output intensity without polarization analyzers. d The high-dimensional Poincaré sphere that describes the states of the generated Poincaré beams under linearly polarized incidences