Polarization-multiplexed spatial filtering in a symmetric TiO ₂ metasurface with an anisotropic van der Waals gap fill

Finite-difference time-domain simulations of a symmetric TiO ₂ nanobar-pair metasurface with a 60 nm α-MoO ₃ gap fill give two Fano resonances that are selected by the input polarization angle, at 885.5 nm ( Q = 50.5) and 893.8 nm ( Q = 44.8).