Pupil plane WFSs for LGS systems of giant telescopes: the case of Ingot

TL;DR

The paper introduces the Ingot wavefront sensor, a novel pupil-plane device designed to improve the sensing of elongated Sodium Laser Guide Stars for next-generation giant telescopes, leveraging 3D optical principles.

Contribution

It presents the design, configurations, and initial analysis of the Ingot WFS, a new approach for LGS wavefront sensing addressing current limitations.

Findings

Initial laboratory tests show promising optical performance.

Comparative analysis indicates advantages over existing WFS methods.

Future development milestones are outlined for the Ingot project.

Abstract

The Ingot WFS belongs to a class of pupil-plane WFSs designed to address the challenges posed by Sodium Laser Guide Stars, and consists of a combination of refractive and reflective surfaces, arranged into a complex prismatic shape that extends in three dimensions. Specifically, it leverages the Scheimpflug principle to sense the full 3D volume of such elongated, time-varying sources, thus optimizing the performance of the next-generation AO-assisted giant telescopes. In this work we discuss the geometrical and optical motivations endorsing the development of this class of WFSs, showing the different configurations we propose to the AO community. We also provide a first order comparative analysis with other approaches and review the state-of-the-art of the Ingot project, including improvements made in the laboratory and future milestones.