High-contrast imaging at first-light of the GMT: the wavefront sensing and control architecture of GMagAO-X

TL;DR

GMagAO-X is a pioneering high-contrast imaging system for the GMT, featuring advanced wavefront sensing and control strategies to address the challenges of large aperture and segmented mirrors.

Contribution

The paper introduces innovative wavefront sensing and control architectures, including holographic sensors and integrated coronagraphic sensors, for the first high-contrast imaging system on ELTs.

Findings

Development of the Holographic Dispersed Fringe Sensor for differential piston measurement

Implementation of integrated coronagraphic wavefront sensors for non-common path aberration control

Design of a flexible, multi-channel wavefront sensing system for GMagAO-X

Abstract

The Giant Magellan Adaptive Optics eXtreme (GMagAO-X) instrument is a first-light high-contrast imaging instrument for the Giant Magellan Telescope (GMT). GMagAO-X's broad wavelength range and the large 25-meter aperture of the GMT creates new challenges: control of all 21.000 actuators; phasing GMT's segmented primary mirror to nm levels; active control of atmospheric dispersion to sub milli-arcsecond residuals; no chromatic pupil shear to minimize chromatic compensation errors; integrated focal plane wavefront sensing and control (WFSC). GMagAO-X will have simultaneous visible and infra-red WFS channels to control the 21.000 actuator DM. The infra-red arm will be flexible by incorporating switchable sensors such as the pyramid or Zernike WFS. One innovation that we developed for GMagAO-X is the Holographic Dispersed Fringe Sensor that measures differential piston. We have also developed several integrated coronagraphic wavefront sensors to control non-common path aberrations exactly where we need to sense them. We will discuss the key components of the WFSC strategies for GMagAO-X that address the challenges posed by the first high-contrast imaging system on the ELTs.