Design and development of a freeform active mirror for an astronomy application

TL;DR

This paper presents a new freeform active mirror system for astronomy that combines innovative manufacturing and active correction to improve optical performance in large telescopes.

Contribution

It introduces a novel hydroforming manufacturing method and an active array design to address freeform mirror fabrication and error compensation in astronomical instruments.

Findings

Successful design of a freeform active mirror system

Prototype development of hydroformed mirror and active array

Potential for improved optical performance in telescopes

Abstract

The advent of extremely large telescopes will bring unprecedented light-collecting power and spatial resolution, but it will also lead to a significant increase in the size and complexity of focal-plane instruments. The use of freeform mirrors could drastically reduce the number of components in optical systems. Currently, manufacturing issues limit the common use of freeform mirrors at short wavelengths. This article outlines the use of freeform mirrors in astronomical instruments with a description of two efficient freeform optical systems. A new manufacturing method is presented which seeks to overcome the manufacturing issues through hydroforming of thin polished substrates. A specific design of an active array is detailed, which will compensate for residual manufacturing errors, thermoelastic deformation, and gravity-induced errors during observations. The combined hydroformed mirror and the active array comprise the Freeform Active Mirror Experiment, which will produce an accurate, compact, and stable freeform optics dedicated to visible and near-infrared observations.