Polarization preservation of linear astigmatism-free imaging systems with multiple conic mirrors

Polarization crosstalk and linear astigmatism are two principal factors that impair the optical performance of unobscured off-axis reflective systems owing to the absence of axial symmetry. In systems comprising two conic mirrors, polarization crosstalk can be minimized when the linear astigmatism-free (LAF) condition is satisfied. This study extends the polarization analysis and theoretically demonstrates that polarization crosstalk can be concurrently minimized with the LAF condition in systems with an arbitrary number of conic mirrors. A case study indicates that a system satisfying the LAF condition exhibits optical characteristics identical to those of the on-axis counterpart from the perspectives of both geometrical and physical optics.