Imaging spatial-helical mode interference of single photons

We present a study of the imaging of the interference of spatial-helical modes of single photons. This work includes a mathematical treatment that accounts for the direction of propagation and spatial mode degrees of freedom in the situation where light travels through an interferometer that prepares the light in distinct spatial modes and makes them interfere. We present results of the interference at the single photon level of the spatialhelical modes with topological charge 1 and 0. The results are consistent with the expectation that each photon carries the entire spatial mode information.