  A directional photon-assisted resonant chiral tunneling through a bilayer
graphene barrier is considered. An external electromagnetic field applied to
the barrier switches the transparency $T$ in the longitudinal direction from
its steady state value T=0 to the ideal T=1 at no energy costs. The switch
happens because the a.c. field affects the phase correlation between the
electrons and holes inside the graphene barrier changing the whole angular
dependence of the chiral tunneling (directional photoelectric effect). The
suggested phenomena can be implemented in relevant experiments and in various
sub-millimeter and far-infrared optical electronic devices.
