  We report polarimetric measurements of geometric phases that are generated by
evolving polarized photons along non-geodesic trajectories on the Poincar\'e
sphere. The core of our polarimetric array consists of seven wave plates that
are traversed by a single photon beam. With this array any SU(2) transformation
can be realized. By exploiting the gauge invariance of geometric phases under
U(1) local transformations, we nullify the dynamical contribution to the total
phase, thereby making the latter coincide with the geometric phase. We
demonstrate our arrangement to be insensitive to various sources of noise
entering it. This makes the single-beam, polarimetric array a promising,
versatile tool for testing robustness of geometric phases against noise.
