End-to-end polarization aberrations simulation for the Decadal Survey Testbed (DST-2)

The Habitable Worlds Observatory (HWO) aims to directly image Earth-like exoplanets to characterize their atmospheres and detect biosignatures by achieving a starlight suppression of 10⁻¹⁰. Among the many challenges in obtaining a contrast of 10⁻¹⁰, polarization-dependent amplitude and phase aberrations generated from Fresnel reflection coefficients from the optical surfaces are critical, as they cannot be completely compensated by wavefront sensing and control system. Different technologies required for the HWO are being developed and tested on the Decadal Survey Testbed 2, for which the polarization aberrations from the OAPs, DMs, and coronagraph masks have to be modeled and analyzed. This paper presents end-to-end simulations of polarization aberrations for the Decadal Survey Testbed 2. We estimate the Jones pupils before the focal plane mask and perform diffraction simulations for two different coronagraph masks, vector vortex and shaped pupil, to assess the contrast performance. Our simulations show that the Jones pupils indicate the dominant polarization aberrations as retardance tilt and defocus, contributing ⪅10⁻¹⁰ to the contrast budget.