PEMC, Simple Skewon, and minkowskian isotropic media: Classification of bi-isotropic metamaterials

In this contribution, a new classification of a certain class of metamaterials is presented. The media under discussion are bi-isotropic, in other words their response is not dependent on the vector direction of the electric and magnetic fields of excitation. The classification covers as special cases the recently introduced PEMC and Simple Skewon materials. The determinant of the medium matrix of this class of materials is unity which leads to interesting consequences due to the “unity-refractiveness” of the medium.