  Inversion-symmetric crystals are optically isotropic and thus naively not
expected to show dichroism effects in optical absorption and photoemission
processes. Here, we find a strong linear dichroism effect (up to 42.4%) in the
conduction band of inversion-symmetric bilayer MoS$_2$, when measuring energy-
and momentum-resolved snapshots of excited electrons by time- and
angle-resolved photoemission spectroscopy. We model the polarization-dependent
photoemission intensity in the transiently-populated conduction band using the
semiconductor Bloch equations and show that the observed dichroism emerges from
intralayer single-particle effects within the isotropic part of the dispersion.
This leads to optical excitations with an anisotropic momentum-dependence in an
otherwise inversion symmetric material.
