Magnetorheological elastomer-based deformable mirror using polydimethylsiloxane (PDMS) membrane

Deformable mirrors are widely used in astronomy, laser communications, and vision science, but conventional contact-based designs are limited by small achievable strokes (< 10 µm). To address this limitation, we developed a contactless deformable mirror based on a magnetorheological elastomer membrane actuated by an array of permanent magnets. The 50 mm diameter, 275 µm thick membrane, composed of PDMS with magnetite nanoparticles, exhibited surface roughness between 3 - 7 nm. Under magnetic flux densities from 21 mT to 77 mT, the mirror achieved deformations up to 0.97 mm using a 37 magnet hexagonal array. Numerical simulations performed in COMSOL showed excellent agreement with experiments, confirming the potential of magnetic actuation to overcome the stroke limitations of conventional deformable mirrors.