  As known from Einstein's theory of general relativity, the propagation of
light in the presence of a massive object is affected by gravity. In this work,
we discuss whether the effect of gravitational light bending can be observed in
Earth-based experiments, using high-finesse optical cavities. In order to do
this, we theoretically investigate the dynamics of electromagnetic waves in the
spacetime of a homogeneous gravitational field and give an analytical
expression for the resulting modifications to Gaussian beam propagation. This
theoretical framework is used to calculate the intensity profile at the output
of a Fabry-P\'erot cavity and to estimate the imprints of Earth's gravity on
the cavity output signal. In particular, we found that gravity causes an
asymmetry of the output intensity profile. Based on that, we discuss a
measurement scheme, that could be realized in facilities like the GEO600
gravitational wave detector and the AEI 10 m detector prototype.
