Revisit of fishnet metamaterials: From viewpoint of dimensionality, symmetry, and designs of unit cell

Physical insight for fishnet metamaterials (MMs) has been advanced further for a few years. The resonances are systematically described by a first-principles approach, that is, eigenmode analysis for perforated metal-insulator-metal structures. Here we provide more general understandings and underlying physics of fishnet MMs from viewpoint of dimensionality, symmetry, and designs of unit cell. In particular, it turns out that negative refraction effect in fishnet MMs is supported by emergence of linearly crossing dispersion or photonic Dirac cone.