Active correction of aperture discontinuities (ACAD) for space telescope pupils: a parametic analysis

TL;DR

This paper analyzes the ACAD method, which uses two deformable mirrors to correct aperture discontinuities in space telescopes, aiming to improve high-contrast imaging by exploring various parameters and configurations.

Contribution

It provides a detailed parametric analysis of the ACAD method, including simulation setup and preliminary results for space telescope pupils, advancing understanding of its effectiveness.

Findings

ACAD can effectively minimize aperture discontinuities.

Parameter choices significantly impact correction performance.

Preliminary results show promise for space telescope applications.

Abstract

As the performance of coronagraphs improves, the achievable contrast is more and more dependent of the shape of the pupil. The future generation of space and ground based coronagraphic instruments will have to achieve high contrast levels on on-axis and/or segmented telescopes. To correct for the high amplitude aberrations introduced by secondary mirror structures and segmentation of the primary mirror, we explore a two deformable mirror (DM) method. The major difficulty of several DM methods is the non-linear relation linking actuator strokes to the point spread function in the coronagraph focal plane. The Active Compensation of Aperture Discontinuities (ACAD) method is achieving this minimization by solving a non linear differential Monge Ampere equation. Once this open loop method have reached the minimum, a close-loop stroke minimization method can be applied to correct for phase and amplitude aberrations to achieve the ultimate contrast. In this paper, I describe the results of the parametric analysis that that I have undertaken on this method. After recalling the principle of the method, I will described the explored parameter space (deformable mirror set-up, shape of the pupil, bandwidth, coronagraph designs). I will precisely described the way I simulated the Vortex coronagraph for this numerical simulation. Finally I will present the preliminary results of this parametric analysis for space telescope pupils only.