  The charge susceptibility of twisted bilayer graphene is investigated in the
Dirac cone, respectively random-phase approximation. For small enough twist
angles $\theta\lesssim 2^\circ$ we find weakly Landau damped interband
plasmons, i.~e., collective excitonic modes which exist in the undoped
material, with an almost constant energy dispersion. In this regime, the loss
function can be described as a Fano resonance and we argue that these
excitations arise from the interaction of quasi-localised states with the
incident light field. These predictions can be tested by nano-infrared imaging
and possible applications include a "perfect" lens without the need of
left-handed materials.
