High-contrast imaging at first light of the GMT: optimized coatings enabling high-throughput observations for GMagAO-X

The Giant Magellan Telescope’s (GMT) high angular resolution and light collecting area are key in enabling its mission to characterize the atmospheres of rocky exoplanets. The high-contrast imaging instrument GMagAO-X will enable high-angular resolution due to its advanced wavefront sensing and control (WFS&C) techniques and coronagraphic imaging capability. However, to support high-fidelity WFS&C many intermediate optics are necessary. For commercially available coatings, the cumulative throughput of GMagAO-X ranges from 5-15%. To enhance the throughput of GMagAO-X we present a design study of customized optical coatings that enable a high broadband throughput. We implement these coatings in a polarization ray trace model of the GMagAO-X optics and investigate whether (chromatic) polarization aberrations are introduced by these coatings. These coating designs will increase the throughput of GMagAO-X significantly and bring the detection of bio-signatures within reach. We will present the results of our coating optimization strategy for high-contrast imaging instruments.