  Exceptional points, which are topological non-Hermitian degeneracies, show up
in the collective mode spectrum of Fermi Liquids with high angular momentum
interactions. In this paper, we look for signatures of these non-trivial
singularities by computing the AC conductivity of Fermi liquids with dipolar
and quadrupolar interactions in a narrow slab. We show that the finite size of
the slab imprints clear signatures of the structures of the collective mode
spectrum in the conductivity as well as in the dephasing between the electric
field and the current density in a wide range of coupling constants. In
particular, we show the fingerprints of exceptional points, observed in the
weak attractive dipolar and/or quadrupolar regime. The main result does not
depend on the specific model of quasi-particle interactions. We also discuss
some actual compounds where these phenomena could be experimentally observed.
