Linearization of the response of a 91-actuator magnetic liquid deformable mirror

TL;DR

This paper demonstrates a novel technique for linearizing the response of a 91-actuator magnetic liquid deformable mirror using a superposed uniform magnetic field, enabling precise wavefront control.

Contribution

The authors introduce a new method that linearizes the deformable mirror response, allowing accurate wavefront shaping with a ferrofluid-based mirror.

Findings

Linear response achieved with superposed magnetic field

Successful generation of the first 36 Zernike polynomials

Predicted wavefront amplitudes up to 30 μm with high accuracy

Abstract

We present the experimental performance of a 91-actuator deformable mirror made of a magnetic liquid (ferrofluid) using a new technique that linearizes the response of the mirror by superposing a uniform magnetic field to the one produced by the actuators. We demonstrate linear driving of the mirror using influence functions, measured with a Fizeau interferometer, by producing the first 36 Zernikes polynomials. Based on our measurements, we predict achievable mean PV wavefront amplitudes of up to 30 {\mu}m having RMS residuals of {\lambda}/10 at 632.8 nm. Linear combination of Zernikes and over-time repeatability are also demonstrated.