Magnetic liquid deformable mirrors for astronomical applications:Active correction of optical aberrations from lower-grade optics and support system

TL;DR

This paper introduces Magnetic Liquid Deformable Mirrors (MLDMs) with high stroke capabilities, demonstrating their potential for correcting optical aberrations in large telescopes and improving astronomical imaging.

Contribution

The paper presents a new MLDM prototype with linearized response, high stroke, and potential for correcting aberrations in large, lower-quality optics in astronomy.

Findings

Demonstrated high-actuator strokes in MLDM prototype

Validated linear response through superimposed magnetic fields

Estimated parameters for practical astronomical applications

Abstract

Deformable mirrors are increasingly used in astronomy. However, they still are limited in stroke for active correction of high amplitude optical aberrations. Magnetic Liquid deformable mirrors (MLDMs) are a new technology that has advantages of high-amplitude deformations and low costs. In this paper we demonstrate extremely high strokes and inter-actuator strokes achievable by MLDMs which can be used in astronomical instrumentation. In particular, we consider the use of such a mirror to suggest an interesting application for the next generation of large telescopes. We present a prototype 91-actuator deformable mirror made of a magnetic liquid (ferrofluid). This mirror uses a technique that linearizes the response of such mirrors by superimposing a large and uniform magnetic field to the magnetic field produced by an array of small coils. We discuss experimental results that illustrate the performance of MLDMs. A most interesting application of MLDMs comes from the fact they could be used to correct the aberrations of large and lower optical quality primary mirrors held by simple support systems. We estimate basic parameters of the needed MLDMs, obtaining reasonable values.