Polarization aberration analysis of the advanced x-ray astrophysics facility telescope assembly

The advanced x-ray astrophysics facility (AXAF) telescope consists of six concentric paraboloid-hyperboloid pairs of mirrors that operate near grazing incidence. Because of the substantial polarization effects at large angles of incidence there has been concern regarding the feasibility of doing polarimetry near the telescope focal plane. The primary mirror is shown to act as a tangentially directed half-wave linear retarder and to almost completely depolarize the linearly polarized component of the light. The secondary mirror introduces an additional half-wave of linear retardance. The two-mirror telescope assembly acts as a tangentially directed one-wave linear retarder. Each mirror depolarizes alone but together the two-mirror assembly preserves the polarization state. The net instrumental polarization effects are small and polarimetry is feasible with AXAF.

The polarization aberration function for the telescope is derived by using Jones calculus. Polarization aberration functions are used to calculte the effect of instrumental polarization on the transmitted wave front and the polarization state that is due to the primary mirror and the telescope assembly.