  In this work, we describe a method to realize 3D Weyl semimetal by coupling
multilayers of honeycomb optical lattice in the presence of a pair of Raman
lasers. The Raman lasers render each isolated honeycomb layer a Chern
insulator. With finite interlayer coupling, the bulk gap of the system closes
at certain out-of-plane momenta due to Raman assisted tunnelling and result in
the Weyl semimetal phase. Using experimentally relevant parameters, we show
that both one and two pairs of Weyl points can be realized by tuning the
interlayer coupling strength. We suggest that Landau-Zener tunnelling can be
used to detect Weyl points and show that the transition probability increases
dramatically when Weyl point emerges. The realization of chiral anomaly by
using a magnetic field gradient is also discussed.
