Dark zone maintenance results for segmented aperture wavefront error drift in a high contrast space coronagraph

TL;DR

This paper demonstrates a dark zone maintenance algorithm on a laboratory testbed with a segmented aperture, showing its effectiveness in correcting wavefront drifts caused by thermal and mechanical instabilities for space coronagraphs.

Contribution

It presents a novel dark zone maintenance algorithm tested on a segmented aperture system with deformable mirrors, addressing wavefront drift correction in high contrast space imaging.

Findings

Effective correction of wavefront drifts in laboratory conditions

Successful maintenance of dark zone across multiple wavelengths

Demonstrated correction with segmented aperture and deformable mirrors

Abstract

Due to the limited number of photons, directly imaging planets requires long integration times with a coronagraphic instrument. The wavefront must be stable on the same time scale, which is often difficult in space due to thermal variations and other mechanical instabilities. In this paper, we discuss the implications on future space mission observing conditions of our recent laboratory demonstration of a dark zone maintenance (DZM) algorithm. The experiments are performed on the High-contrast imager for Complex Aperture Telescopes (HiCAT) at the Space Telescope Science Institute (STScI). The testbed contains a segmented aperture, a pair of continuous deformable mirrors (DMs), and a lyot coronagraph. The segmented aperture injects high order wavefront aberration drifts into the system which are then corrected by the DMs downstream via the DZM algorithm. We investigate various drift modes including segmented aperture drift, all three DMs drift simultaneously, and drift correction at multiple wavelengths.