Visible extreme adaptive optics for GMagAO-X with the triple-stage AO architecture (TSAO)

TL;DR

This paper proposes a triple-stage adaptive optics system for extremely large telescopes, combining multiple deformable mirrors and sensors to achieve high Strehl ratios in the visible spectrum.

Contribution

Introduction of a novel triple-stage AO architecture for GMagAO-X, enabling decoupled control loops and improved high-order correction for extremely large telescopes.

Findings

Demonstrated the feasibility of the TSAO architecture for high-order correction.

Showed that decoupled control loops simplify AO system management.

Achieved high Strehl ratios in simulations for the GMagAO-X system.

Abstract

The Extremely Large Telescopes will require hundreds of actuators across the pupil for high Strehl in the visible. We envision a triple-stage AO (TSAO) system for GMT/GMagAO-X to achieve this. The first stage is a 4K DM controlled by an IR pyramid wavefront sensor that provides the first order correction. The second stage contains the high-order parallel DM of GMagAO-X that has 21000 actuators and contains an interferometric delay line for phasing of each mirror segment. This stage uses a Zernike wavefront sensor for high-order modes and a Holographic Dispersed Fringe Sensor for segment piston control. Finally, the third stage uses a dedicated 3K dm for non-common path aberration control and the coronagraphic wavefront control by using focal plane wavefront sensing and control. The triple stage architecture has been chosen to create simpler decoupled control loops. This work describes the performance of the proposed triple-stage AO architecture for ExAO with GMagAO-X.