Experimental analysis of the achromatic performance of a vector vortex coronagraph

Abstract

The vector vortex coronagraph is an instrument designed for direct detection and spectroscopy of exoplanets over a broad spectral range. Our team is working towards demonstrating contrast performance commensurate with imaging temperate, terrestrial planets orbiting solar-type stars using the High Contrast Imaging Testbed facility at NASA's Jet Propulsion Laboratory. To date, the best broadband performance achieved is $\sim$10${}^{-8}$ raw contrast over a bandwidth of $\Delta \lambda /\lambda$=10\% in the visible regime (central wavelengths of 550-750 nm), while monochromatic tests yield much deeper contrast ($\sim$10${}^{-9}$ or better). In this study, we analyze the main performance limitations on the testbeds so far, focusing on the quality of the focal plane mask manufacturing. We measure the polarization properties of the masks and the residual electric field in the dark hole as a function of wavelength. Our results suggest that the current performance is limited by localized defects in the in the focal plane masks. A new generation of masks is under test that have fewer defects and promise performance improvements.

To appear in SPIE Proceedings Volume 11443, Space Telescopes and Instrumentation 2020: Optical, Infrared, and Millimeter Wave

References in corpus (2)

• The Habitable Exoplanet Observatory (HabEx) Mission Concept Study Final Report
• Design, pointing control, and on-sky performance of the mid-infrared vortex coronagraph for the VLT/NEAR experiment

Cited by in corpus (4)

• Topological Designs for Scalar Vortex Coronagraphs
• Design of the vacuum high contrast imaging testbed for CDEEP, the Coronagraphic Debris and Exoplanet Exploring Pioneer
• High Contrast Demonstrations of Novel Scalar Vortex Coronagraph Designs at the High Contrast Spectroscopy Testbed
• New method to achieve the proper polarization state for a vector vortex coronagraph