Low-symmetry lattices of non-chiral meta-atoms for resonant handedness-preserving reflection
Mirrors that preserve the handedness of optical radiation upon reflection are an essential building block for the design of numerous resonant nanophotonic structures with capabilities for enantiomeric discrimination. Ordinary metallic and Bragg dielectric mirrors are not suitable in these context since they flip handedness of electromagnetic field upon reflection around normal incidence. While there has been considerable progress in the development of such reflecting structures, this research area remains largely unexplored. Here, we present a detailed numerical and theoretical analysis of the potential of low-symmetry periodic lattices composed of high-symmetry non-chiral meta-atoms for resonant reflection with handedness preservation (HP). Using full-wave numerical simulations, we analyze a family of rhombic and monoclinic (oblique) lattices of circular dielectric disks and/or holes, and in each identify the regime of near-perfect HP reflection. We study the robustness of these structures to geometric deviations, material losses, and incidence angle. Finally, we describe the resonant HP response of these structures using the coupled-mode theory formalism.