Potentials in bi-anisotropic media

Potential representations for electromagnetic fields are considered for linear bi-anisotropic media. Representations in terms of two vector potentials are possible for any bi-anisotropic media. However, representations in terms of two scalar potentials are associated with media in which fields can be decomposed in two partial fields with special polarization restrictions. This kind of media have been studied before and they define the class of decomposable bi-anisotropic media. Potential representations in terms of two scalar potentials are derived for fields in decomposable bi-anisotropic media in two different ways and the results are shown to coincide. The expressions obtained give the previously known potential representations in isotropic and decomposable anisotropic media as special cases