A metasurface with bidirectional hyperbolic surface modes and position-sensing applications

We have theoretically and experimentally studied resonance-induced hyperbolic metasurfaces and proved that they offer an efficient way to introduce Fano-resonance and decrease the Q-factor in our system in order to create hyperbolic isofrequency contours (IFCs) along two orthogonal directions. A metasurface with a continuous topological transition for such IFCs has been designed and experimentally implemented. In particular, two independent collimation frequencies can be found to correspond to the transition frequencies in orthogonal directions. As a consequence, we experimentally demonstrated that the metasurface can function as a position sensor by utilizing bidirectional hyperbolic surface waves, introducing a new avenue for coordinate sensing.