# Lasing with Topological Weyl Semimetal. (arXiv:1905.05799v1 [physics.optics])

Lasing behavior of optically active planar topological Weyl semimetal (TWS)
is investigated in view of Kerr and Faraday rotations. Robust topological
character of TWS is revealed by the presence of Weyl nodes and relevant surface
conductivities. We focus our attention on the surfaces where no fermi arcs are
formed, and thus Maxwell equations contain topological terms. We explicitly
demonstrate that two distinct lasing modes arise because of the presence of
effective refractive indices which lead to the birefringence phenomena.
Transfer matrix is constructed in such a way that reflection and transmission
amplitudes involve $2\times2$ matrix-valued components describing the bimodal
character of the TWS laser. We provide associated parameters of the laser
system yielding the optimal impacts. Our proposal is supported by the
corresponding graphical demonstrations. Our observations and predictions
suggest a concrete way of forming TWS laser and coherent perfect absorber and
are awaited to be confirmed by an experimental realization based on our
computations.