Mueller matrix-based calculation model for extracting polarization parameters in full-wave simulation of all-dielectric Pancharatnam–Berry (PB)-phase metasurfaces

In this study, the Mueller matrix of all-dielectric Pancharatnam–Berry (PB)-phase metasurfaces was retrieved using finite-difference time-domain (FDTD) simulation, Stokes–Mueller calculus, and Lu–Chipman decomposition. The polarization properties are discussed for nanofin-shaped PB-phase metasurfaces made of GaN and Nb₂O₅ and L-shaped PB-phase metasurfaces made of GaN. The results show that both the nanofin-shaped and L-shaped PB-phase GaN metasurfaces are optically equivalent to a linear-diattenuating retarder, and the nanofin-shaped PB-phase Nb₂O₅ metasurface is optically equivalent to a linear phase retarder. The PB-phase GaN metasurface exhibits stronger diattenuation and lower transmittance than the Nb₂O₅ metasurface due to the inherent defect absorption in the visible range. With a similar refractive index but barely any absorption, Nb₂O₅ is a more suitable material for PB-phase metasurfaces in the visible range than GaN.