SUPPPPRESS: prototyping and testing liquid crystal vector vortex coronagraphs with reduced polarization leakage

Journal of Astronomical Telescopes Instruments and Systems, vol. 12, pp. 1–22

Abstract

The vortex coronagraph is one of the most promising candidates for the Habitable Worlds Observatory due to its excellent theoretical performance for an off-axis telescope. A practical realization can be achieved using liquid crystal polymers to form a vector vortex coronagraph (VVC). Reaching the 10−10 contrast required for Earth-like planet detection is, however, limited by polarization leakage caused by wavelength-dependent deviations from half-wave retardance. This effect can be mitigated using multi-layer twisted retarders to minimize leakage and by combining the VVC with multiple polarization gratings (mgVVC) to diffract the polarization leakage out of the science path. We present recent progress within the European-Space-Agency-funded Substantiating Unique Patterned Polarization-sensitive Polymer Photonics for Research of Exoplanets with Space-based Systems project, which aims to advance the manufacturing, assembly, and testing of high-performance VVCs. Central singularities of 2 and 6 μm have been achieved for charge 2 and 6 VVCs, respectively, with patterning accuracies better than 1-deg root mean square error. Fabrication procedures have been developed to produce individual components with a polarization leakage of 3×10−4 over a 10% bandwidth and 8×10−4 over a 20% bandwidth. We also report on the development of assembly and alignment procedures for mgVVCs and their metrology. Furthermore, we present initial high-contrast tests at the Très Haute Dynamique 2 bench for both regular VVCs and a double-grating VVC. The double-grating VVC reaches an average contrast between 3 and 10λ/D of 2×10−8 over a small bandwidth and 6×10−8 over a 10% bandwidth. Finally, we report on successful space environment tests of the assembled liquid crystal masks.

Authors 18

1. Rico Landman
   Affiliation as printed

   NOVA

2. David S. Doelman Aachen SRON Space Research Organization Netherlands

   Space Research Organisation Netherlands

   Affiliation as printed

   SRON Space Research Organization Netherlands

3. Jeroen Rietjens Aachen SRON Space Research Organization Netherlands

   Space Research Organisation Netherlands

   Affiliation as printed

   SRON Space Research Organization Netherlands

4. Iva Laginja
   Affiliation as printed

   NOVA

5. Pierre Baudoz

   Université Paris Cité · Université Paris Sciences et Lettres · Observatoire de Paris · Sorbonne Université · CY Cergy Paris Université

   Affiliation as printed

   LIRA, Observatoire de Paris, Université PSL, Sorbonne Université, Université Paris Cité, CY Cergy Paris Université

6. Kristien Peeters
   Affiliation as printed

   cosine Remote Sensing B.V

7. Chris Van Dijk
   Affiliation as printed

   cosine Remote Sensing B.V

8. Yuki Nishie
   Affiliation as printed

   ColorLink Japan, Ltd

9. Yuta Watanabe
   Affiliation as printed

   ColorLink Japan, Ltd

10. Alexander B. C. Eigenraam Aachen SRON Space Research Organization Netherlands

    Space Research Organisation Netherlands

    Affiliation as printed

    SRON Space Research Organization Netherlands

11. Mario Vretenar Aachen SRON Space Research Organization Netherlands

    Space Research Organisation Netherlands

    Affiliation as printed

    SRON Space Research Organization Netherlands

12. R. Galicher

    Université Paris Cité · Université Paris Sciences et Lettres · Observatoire de Paris · Sorbonne Université · CY Cergy Paris Université

    Affiliation as printed

    LIRA, Observatoire de Paris, Université PSL, Sorbonne Université, Université Paris Cité, CY Cergy Paris Université

13. Johan Mazoyer

    Université Paris Cité · Université Paris Sciences et Lettres · Observatoire de Paris · Sorbonne Université · CY Cergy Paris Université

    Affiliation as printed

    LIRA, Observatoire de Paris, Université PSL, Sorbonne Université, Université Paris Cité, CY Cergy Paris Université

14. Axel Potier

    Université Paris Cité · Université Paris Sciences et Lettres · Observatoire de Paris · Sorbonne Université · CY Cergy Paris Université

    Affiliation as printed

    LIRA, Observatoire de Paris, Université PSL, Sorbonne Université, Université Paris Cité, CY Cergy Paris Université

15. Mariya Krasteva

    European Space Agency · European Space Research and Technology Centre

    Affiliation as printed

    European Space Agency, ESTEC

16. Matteo Taccola

    European Space Agency · European Space Research and Technology Centre

    Affiliation as printed

    European Space Agency, ESTEC

17. Felix Bettonvil
    Affiliation as printed

    NOVA

18. Frans Snik
    Affiliation as printed

    NOVA