Weyl semimetals are topological materials whose electron quasiparticles obey
the Weyl equation. They possess many unusual properties that may lead to new
applications. This is a tutorial review of the optical properties and
applications of Weyl semimetals. We review the basic concepts and optical
responses of Weyl semimetals, and survey their applications in optics and
thermal photonics. We hope this pedagogical text will motivate further research
on this emerging topic.Comment: Tutorial review, 53 pages, 12 figure