  The excitation spectrum and the collective modes of graphene antidot lattices
(GALs) are studied in the context of a $\pi$-band tight-binding model. The
dynamical polarizability and dielectric function are calculated within the
random phase approximation. The effect of different kinds of disorder, such as
geometric and chemical disorder, are included in our calculations. We highlight
the main differences of GALs with respect to single-layer graphene (SLG). Our
results show that, in addition to the well-understood bulk plasmon in doped
samples, inter-band plasmons appear in GALs. We further show that the static
screening properties of undoped and doped GALs are quantitatively different
from SLG.
