Equivalence of reflection paths of light and Feynman paths in stacked metasurfaces

We show the existence of virtual polarization states during the interaction of modes in metasurface stacks. In support of our findings we experimentally realize a metasurface stack, consisting of an isotropic layer of nanopatches and an anisotropic layer of nanowires. Utilizing an analogy to the interaction of electrons at junctions in mesoscopic electron transport via Feynman paths, we present a semi-analytic description of the modal interaction inside this stack. We then derive a series of all possible reflection paths light can take inside the metasurface stack.