Polarization aberrations in next-generation Giant Segmented Mirror Telescopes (GSMTs)

Astronomy and Astrophysics, vol. 695, pp. A28

Abstract

Context . Direct exo-earth imaging is a key science goal for astronomy in the next decade. This ambitious task imposes a target contrast of ≈10 −7 at wavelengths from I to J -band. In our prior study, we determined that polarization aberrations can limit the achievable contrast to 10 −5 to 10 −6 in the infrared. However, these results assumed a perfect coronagraph coupled to a telescope with an ideal coating on each of the mirrors. Aims . In this study we seek to understand the influence of polarization aberrations from segment-to-segment coating variations on coronagraphy and polarimetry. Methods . We use the Poke open-source polarization ray tracing package to compute the Jones pupil of each GSMT with spatially- varying coatings applied to the segments. The influence of the resultant polarization aberrations is simulated by propagating the Jones pupil through physical optics models of coronagraphs using HCIPy. Results . After applying wavefront control from an ideal adaptive optics system, we determine that the segment-to-segment variations applied limit the performance of coronagraphy to a raw contrast of approximately 10 −8 in I -band, which is 2–3 orders of magnitude lower the target performance for high-contrast imaging systems on the ground. This is a negligible addition to the nominal polarization aberrations for ground-based systems. We further observe negligible degradation in polarimetric imaging of debris disks from segment-to-segment aberrations above and beyond the impact of nominal polarization aberration.

Authors 11

1. Jaren Nicholas Ashcraft

   University of Arizona · University of California, Santa Barbara

   Affiliation as printed

   Department of Physics, University of California, Santa Barbara, CA 93106, USA

   James C. Wyant College of Optical Sciences, University of Arizona, 933N Cherry Avenue, Tucson, AZ 85721, USA

   Steward Observatory, University of Arizona, 933N Cherry Avenue, Tucson, AZ 85721, USA

2. Ramya M. Anche

   University of Arizona

   Affiliation as printed

   Steward Observatory, University of Arizona, 933N Cherry Avenue, Tucson, AZ 85721, USA

3. Sebastiaan Y. Haffert Aachen

   Leiden University · University of Arizona

   Affiliation as printed

   Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands

   Steward Observatory, University of Arizona, 933N Cherry Avenue, Tucson, AZ 85721, USA

4. Justin Hom

   University of Arizona

   Affiliation as printed

   Steward Observatory, University of Arizona, 933N Cherry Avenue, Tucson, AZ 85721, USA

5. Maxwell A. Millar‐Blanchaer

   University of California, Santa Barbara

   Affiliation as printed

   Department of Physics, University of California, Santa Barbara, CA 93106, USA

6. Ewan S. Douglas

   University of Arizona

   Affiliation as printed

   Steward Observatory, University of Arizona, 933N Cherry Avenue, Tucson, AZ 85721, USA

7. Frans Snik Aachen

   Leiden University

   Affiliation as printed

   Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands

8. R. G. van Holstein

   European Southern Observatory

   Affiliation as printed

   European Southern Observatory (ESO), Alonso de Córdova 3107, Vitacura, Casilla 19001, Santiago de Chile, Chile

9. Kyle Van Gorkom

   University of Arizona

   Affiliation as printed

   Steward Observatory, University of Arizona, 933N Cherry Avenue, Tucson, AZ 85721, USA

10. Warren Skidmore

    TMT Observatory

    Affiliation as printed

    TMT International Observatory LLC, 100 W. Walnut St., Suite 300, Pasadena, CA 91124, USA

11. Manxuan Zhang

    University of California, Santa Barbara

    Affiliation as printed

    Department of Physics, University of California, Santa Barbara, CA 93106, USA