  We present systematic theoretical studies of both bulk and surface
electromagnetic eigenmodes, or polaritons, in Weyl semimetals. We derive the
tensors of bulk and surface conductivity taking into account all possible
combinations of the optical transitions involving bulk and surface electron
states. We show how information about electronic structure of Weyl semimetals,
such as position and separation of Weyl nodes, Fermi energy, and Fermi arc
surface states, can be unambiguously extracted from measurements of the
dispersion, transmission, reflection, and polarization of electromagnetic
waves.
