  Optical modes in anisotropic slab waveguides with topological and chiral
magnetoelectric effects are investigated analytically, by deriving the
closed-form characteristic equations of the modes and hence computing the
dispersion-diagrams. In order to compute the characteristic equations, a
vector-potential approach is introduced by incorporating a generalized Lorentz
gauge, and the corresponding Helmholtz equations are derived correspondingly.
It will be shown that the formation of the complex modes and hybridization of
the optical modes in such slab waveguides is inevitable. Moreover, when the
tensorial form of the permittivity in the waveguide allows for a hyperbolic
dispersion, complex transition from the photonic kinds of modes to the
plasmonic modes is expected.
