Polarization-Multiplexed Spatial Filtering in a Symmetric \ce{TiO2} Metasurface with an Anisotropic van der Waals Gap Fill

Finite-difference time-domain simulations of a symmetric \ce{TiO2} nanobar-pair metasurface with a 60~nm $α$-\ce{MoO3} 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 ($Q=44.8$). Both channels act as spatial high-pass filters a