Magnetically induced topological transitions of hyperbolic dispersion in biaxial gyrotropic media

Tetra-hyperbolic and tri-hyperbolic optical phases in anisotropic metamaterials without magnetoelectric coupling due to hybridization of plasmonic and magnetic Bloch high-k polaritons

“…Technically, the tri-and tetra-hyperbolic phases require magnetoelectric coupling and in the "mono"-anisotropic regime (i. e. without magnetoelectric coupling) only non-, mono-, and bi-hyperbolic phases can be achieved [10]. However, as Tuz and Fesenko demonstrate now [11], even the "mono"-anisotropic materials can support iso-frequency topologies, resembling tetra-hyperbolic (see Fig. 3(d) in Ref.…”

“…The dispersion of the high-k modes can be obtained from investigation of the matrix 𝑍 ̂𝑛≫1 from Eq. (11), which turns into…”