Laboratory demonstration of the triple-grating vector vortex coronagraph

arXiv (Cornell University)

Abstract

The future Habitable Worlds Observatory aims to characterize the atmospheres of rocky exoplanets around solar-type stars. The vector vortex coronagraph (VVC) is a main candidate to reach the required contrast of $10^{-10}$. However, the VVC requires polarization filtering and every observing band requires a different VVC. The triple-grating vector vortex coronagraph (tgVVC) aims to mitigate these limitations by combining multiple gratings that minimize the polarization leakage over a large spectral bandwidth. In this paper, we present laboratory results of a tgVVC prototype using the In-Air Coronagraphic Testbed (IACT) facility at NASA's Jet Propulsion Laboratory and the Space Coronagraph Optical Bench (SCoOB) at the University of Arizona Space Astrophysics Lab (UASAL). We study the coronagraphic performance with polarization filtering at 633 nm and reach a similar average contrast of $2 \times 10^{-8}$ between 3-18 $λ/D$ at the IACT, and $6 \times 10^{-8}$ between 3-14 $λ/D$ at SCoOB. We explore the limitations of the tgVVC by comparing the testbed results. We report on other manufacturing errors and ways to mitigate their impact.

Authors 8

1. David S. Doelman Aachen Leiden Observatory SRON Netherlands Institute for Space Research

   Leiden University · Leiden Observatory · Space Research Organisation Netherlands

   Affiliation as printed

   Leiden Observatory , Leiden University , P.O. Box 9513 , 2300 RA Leiden , The Netherlands

   SRON Netherlands Institute for Space Research , Niels Bohrweg 4 , 2333 CA , Leiden , The Netherlands

2. Mireille Ouellet Aachen Leiden Observatory

   Leiden University · Leiden Observatory

   Affiliation as printed

   Leiden Observatory , Leiden University , P.O. Box 9513 , 2300 RA Leiden , The Netherlands

3. Axel Potier

   California Institute of Technology · Jet Propulsion Laboratory

   Affiliation as printed

   Jet Propulsion Laboratory , California Institute of Technology , Pasadena , California 91109 , USA

4. Garreth Ruane

   California Institute of Technology · Jet Propulsion Laboratory

   Affiliation as printed

   Jet Propulsion Laboratory , California Institute of Technology , Pasadena , California 91109 , USA

5. Kyle Van Gorkom

   University of Arizona

   Affiliation as printed

   University of Arizona , Steward Observatory , Tucson , Arizona , United States

6. Sebastiaan Y. Haffert

   University of Arizona

   Affiliation as printed

   University of Arizona , Steward Observatory , Tucson , Arizona , United States

7. Ewan S. Douglas

   University of Arizona

   Affiliation as printed

   University of Arizona , Steward Observatory , Tucson , Arizona , United States

8. Frans Snik Aachen Leiden Observatory

   Leiden University · Leiden Observatory

   Affiliation as printed

   Leiden Observatory , Leiden University , P.O. Box 9513 , 2300 RA Leiden , The Netherlands